From: Timothy Hoffman <4001421+tim-hoffman@users.noreply.github.com>
Date: Fri, 16 Jul 2021 15:55:33 +0000 (-0500)
Subject: Replace StringBuffer with StringBuilder and other minor String optimizations
X-Git-Tag: rel_3_29_0_ga~2^2~1
X-Git-Url: https://source.dussan.org/?a=commitdiff_plain;h=b4279f68174129f8b7b6180e6782641884daf013;p=javassist.git

Replace StringBuffer with StringBuilder and other minor String optimizations
---

diff --git a/src/main/javassist/ClassPoolTail.java b/src/main/javassist/ClassPoolTail.java
index 1aa948f7..d86cd768 100644
--- a/src/main/javassist/ClassPoolTail.java
+++ b/src/main/javassist/ClassPoolTail.java
@@ -54,7 +54,7 @@ final class DirClassPath implements ClassPath {
             char sep = File.separatorChar;
             String filename = directory + sep
                 + classname.replace('.', sep) + ".class";
-            return new FileInputStream(filename.toString());
+            return new FileInputStream(filename);
         }
         catch (FileNotFoundException e) {}
         catch (SecurityException e) {}
@@ -187,7 +187,7 @@ final class JarClassPath implements ClassPath {
 
     @Override
     public String toString() {
-        return jarfileURL == null ? "<null>" : jarfileURL.toString();
+        return jarfileURL == null ? "<null>" : jarfileURL;
     }
 }
 
@@ -200,7 +200,7 @@ final class ClassPoolTail {
 
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer();
+        StringBuilder buf = new StringBuilder();
         buf.append("[class path: ");
         ClassPathList list = pathList;
         while (list != null) {
diff --git a/src/main/javassist/CtBehavior.java b/src/main/javassist/CtBehavior.java
index da7cff04..595da505 100644
--- a/src/main/javassist/CtBehavior.java
+++ b/src/main/javassist/CtBehavior.java
@@ -100,7 +100,7 @@ public abstract class CtBehavior extends CtMember {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(' ');
         buffer.append(getName());
         buffer.append(' ');
diff --git a/src/main/javassist/CtClass.java b/src/main/javassist/CtClass.java
index f227019f..06f80438 100644
--- a/src/main/javassist/CtClass.java
+++ b/src/main/javassist/CtClass.java
@@ -200,12 +200,12 @@ public abstract class CtClass {
      */
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer(getClass().getName());
-        buf.append("@");
+        StringBuilder buf = new StringBuilder(getClass().getName());
+        buf.append('@');
         buf.append(Integer.toHexString(hashCode()));
-        buf.append("[");
+        buf.append('[');
         extendToString(buf);
-        buf.append("]");
+        buf.append(']');
         return buf.toString();
     }
 
@@ -213,7 +213,7 @@ public abstract class CtClass {
      * Implemented in subclasses to add to the {@link #toString()} result.
      * Subclasses should put a space before each token added to the buffer.
      */
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(getName());
     }
 
diff --git a/src/main/javassist/CtClassType.java b/src/main/javassist/CtClassType.java
index 959ec302..22b873a6 100644
--- a/src/main/javassist/CtClassType.java
+++ b/src/main/javassist/CtClassType.java
@@ -106,7 +106,7 @@ class CtClassType extends CtClass {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         if (wasChanged)
             buffer.append("changed ");
 
@@ -125,7 +125,7 @@ class CtClassType extends CtClass {
             if (ext != null) {
                 String name = ext.getName();
                 if (!name.equals("java.lang.Object"))
-                    buffer.append(" extends " + ext.getName());
+                    buffer.append(" extends ").append(ext.getName());
             }
         }
         catch (NotFoundException e) {
@@ -155,7 +155,7 @@ class CtClassType extends CtClass {
                    memCache.methodHead(), memCache.lastMethod());
     }
 
-    private void exToString(StringBuffer buffer, String msg,
+    private void exToString(StringBuilder buffer, String msg,
                             CtMember head, CtMember tail) {
         buffer.append(msg);
         while (head != tail) {
diff --git a/src/main/javassist/CtField.java b/src/main/javassist/CtField.java
index 892fff82..dbcd82d5 100644
--- a/src/main/javassist/CtField.java
+++ b/src/main/javassist/CtField.java
@@ -128,7 +128,7 @@ public class CtField extends CtMember {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(' ');
         buffer.append(getName());
         buffer.append(' ');
diff --git a/src/main/javassist/CtMember.java b/src/main/javassist/CtMember.java
index 8de480c9..bacfead8 100644
--- a/src/main/javassist/CtMember.java
+++ b/src/main/javassist/CtMember.java
@@ -30,7 +30,7 @@ public abstract class CtMember {
      */
     static class Cache extends CtMember {
         @Override
-        protected void extendToString(StringBuffer buffer) {}
+        protected void extendToString(StringBuilder buffer) {}
         @Override
         public boolean hasAnnotation(String clz) { return false; }
         @Override
@@ -155,13 +155,13 @@ public abstract class CtMember {
 
     @Override
     public String toString() {
-        StringBuffer buffer = new StringBuffer(getClass().getName());
-        buffer.append("@");
+        StringBuilder buffer = new StringBuilder(getClass().getName());
+        buffer.append('@');
         buffer.append(Integer.toHexString(hashCode()));
-        buffer.append("[");
+        buffer.append('[');
         buffer.append(Modifier.toString(getModifiers()));
         extendToString(buffer);
-        buffer.append("]");
+        buffer.append(']');
         return buffer.toString();
     }
 
@@ -172,7 +172,7 @@ public abstract class CtMember {
      * provided first; subclasses should provide additional data such
      * as return type, field or method name, etc.
      */
-    protected abstract void extendToString(StringBuffer buffer);
+    protected abstract void extendToString(StringBuilder buffer);
 
     /**
      * Returns the class that declares this member.
diff --git a/src/main/javassist/CtNewClass.java b/src/main/javassist/CtNewClass.java
index b0a14806..496eaec7 100644
--- a/src/main/javassist/CtNewClass.java
+++ b/src/main/javassist/CtNewClass.java
@@ -45,7 +45,7 @@ class CtNewClass extends CtClassType {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         if (hasConstructor)
             buffer.append("hasConstructor ");
 
diff --git a/src/main/javassist/bytecode/Descriptor.java b/src/main/javassist/bytecode/Descriptor.java
index fc49b876..4e4fd863 100644
--- a/src/main/javassist/bytecode/Descriptor.java
+++ b/src/main/javassist/bytecode/Descriptor.java
@@ -109,7 +109,7 @@ public class Descriptor {
 
         if (arrayDim == 0)
             return name;
-        StringBuffer sbuf = new StringBuffer(name);
+        StringBuilder sbuf = new StringBuilder(name);
         do {
             sbuf.append("[]");
         } while (--arrayDim > 0);
@@ -157,7 +157,7 @@ public class Descriptor {
         if (desc.indexOf(oldname) < 0)
             return desc;
 
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         int head = 0;
         int i = 0;
         for (;;) {
@@ -200,7 +200,7 @@ public class Descriptor {
         if (map == null)
             return desc;
 
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         int head = 0;
         int i = 0;
         for (;;) {
@@ -237,12 +237,12 @@ public class Descriptor {
      * Returns the descriptor representing the given type.
      */
     public static String of(CtClass type) {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         toDescriptor(sbuf, type);
         return sbuf.toString();
     }
 
-    private static void toDescriptor(StringBuffer desc, CtClass type) {
+    private static void toDescriptor(StringBuilder desc, CtClass type) {
         if (type.isArray()) {
             desc.append('[');
             try {
@@ -284,7 +284,7 @@ public class Descriptor {
      * @param paramTypes parameter types
      */
     public static String ofMethod(CtClass returnType, CtClass[] paramTypes) {
-        StringBuffer desc = new StringBuffer();
+        StringBuilder desc = new StringBuilder();
         desc.append('(');
         if (paramTypes != null) {
             int n = paramTypes.length;
@@ -323,7 +323,7 @@ public class Descriptor {
         int i = desc.indexOf(')');
         if (i < 0)
             return desc;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(desc.substring(0, i));
         newdesc.append('L');
         newdesc.append(classname.replace('.', '/'));
@@ -361,7 +361,7 @@ public class Descriptor {
         int i = descriptor.indexOf(')');
         if (i < 0)
             return descriptor;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(descriptor.substring(0, i));
         toDescriptor(newdesc, type);
         newdesc.append(descriptor.substring(i));
@@ -395,7 +395,7 @@ public class Descriptor {
         int i = desc.indexOf(')');
         if (i < 0)
             return desc;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(desc.substring(0, i + 1));
         newdesc.append('L');
         newdesc.append(classname.replace('.', '/'));
@@ -561,7 +561,7 @@ public class Descriptor {
         }
 
         if (arrayDim > 0) {
-            StringBuffer sbuf = new StringBuffer(name);
+            StringBuilder sbuf = new StringBuilder(name);
             while (arrayDim-- > 0)
                 sbuf.append("[]");
 
@@ -719,7 +719,7 @@ public class Descriptor {
 
     static class PrettyPrinter {
         static String toString(String desc) {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             if (desc.charAt(0) == '(') {
                 int pos = 1;
                 sbuf.append('(');
@@ -738,7 +738,7 @@ public class Descriptor {
             return sbuf.toString();
         }
 
-        static int readType(StringBuffer sbuf, int pos, String desc) {
+        static int readType(StringBuilder sbuf, int pos, String desc) {
             char c = desc.charAt(pos);
             int arrayDim = 0;
             while (c == '[') {
diff --git a/src/main/javassist/bytecode/InstructionPrinter.java b/src/main/javassist/bytecode/InstructionPrinter.java
index 6d18a4d4..ae853294 100644
--- a/src/main/javassist/bytecode/InstructionPrinter.java
+++ b/src/main/javassist/bytecode/InstructionPrinter.java
@@ -235,17 +235,17 @@ public class InstructionPrinter implements Opcode {
 
 
     private static String lookupSwitch(CodeIterator iter, int pos) {
-        StringBuffer buffer = new StringBuffer("lookupswitch {\n");
+        StringBuilder buffer = new StringBuilder("lookupswitch {\n");
         int index = (pos & ~3) + 4;
         // default
-        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append("\n");
+        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append('\n');
         int npairs = iter.s32bitAt(index += 4);
         int end = npairs * 8 + (index += 4);
 
         for (; index < end; index += 8) {
             int match = iter.s32bitAt(index);
             int target = iter.s32bitAt(index + 4) + pos;
-            buffer.append("\t\t").append(match).append(": ").append(target).append("\n");
+            buffer.append("\t\t").append(match).append(": ").append(target).append('\n');
         }
 
         buffer.setCharAt(buffer.length() - 1, '}');
@@ -254,10 +254,10 @@ public class InstructionPrinter implements Opcode {
 
 
     private static String tableSwitch(CodeIterator iter, int pos) {
-        StringBuffer buffer = new StringBuffer("tableswitch {\n");
+        StringBuilder buffer = new StringBuilder("tableswitch {\n");
         int index = (pos & ~3) + 4;
         // default
-        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append("\n");
+        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append('\n');
         int low = iter.s32bitAt(index += 4);
         int high = iter.s32bitAt(index += 4);
         int end = (high - low + 1) * 4 + (index += 4);
@@ -265,7 +265,7 @@ public class InstructionPrinter implements Opcode {
         // Offset table
         for (int key = low; index < end; index += 4, key++) {
             int target = iter.s32bitAt(index) + pos;
-            buffer.append("\t\t").append(key).append(": ").append(target).append("\n");
+            buffer.append("\t\t").append(key).append(": ").append(target).append('\n');
         }
 
         buffer.setCharAt(buffer.length() - 1, '}');
diff --git a/src/main/javassist/bytecode/ParameterAnnotationsAttribute.java b/src/main/javassist/bytecode/ParameterAnnotationsAttribute.java
index 49e2646f..ec97d18f 100644
--- a/src/main/javassist/bytecode/ParameterAnnotationsAttribute.java
+++ b/src/main/javassist/bytecode/ParameterAnnotationsAttribute.java
@@ -201,7 +201,7 @@ public class ParameterAnnotationsAttribute extends AttributeInfo {
         StringBuilder sbuf = new StringBuilder();
         for (Annotation[] a : aa) {
             for (Annotation i : a)
-                sbuf.append(i.toString()).append(" ");
+                sbuf.append(i.toString()).append(' ');
 
             sbuf.append(", ");
         }
diff --git a/src/main/javassist/bytecode/SignatureAttribute.java b/src/main/javassist/bytecode/SignatureAttribute.java
index 1a8a62dc..4671b787 100644
--- a/src/main/javassist/bytecode/SignatureAttribute.java
+++ b/src/main/javassist/bytecode/SignatureAttribute.java
@@ -431,7 +431,7 @@ public class SignatureAttribute extends AttributeInfo {
          */
         @Override
         public String toString() {
-            StringBuffer sbuf = new StringBuffer(getName());
+            StringBuilder sbuf = new StringBuilder(getName());
             if (superClass != null)
                 sbuf.append(" extends ").append(superClass.toString());
 
@@ -740,7 +740,7 @@ public class SignatureAttribute extends AttributeInfo {
          */
         @Override
         public String toString() {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             ClassType parent = getDeclaringClass();
             if (parent != null)
                 sbuf.append(parent.toString()).append('.');
@@ -748,7 +748,7 @@ public class SignatureAttribute extends AttributeInfo {
             return toString2(sbuf);
         }
 
-        private String toString2(StringBuffer sbuf) {
+        private String toString2(StringBuilder sbuf) {
             sbuf.append(name);
             if (arguments != null) {
                 sbuf.append('<');
@@ -773,7 +773,7 @@ public class SignatureAttribute extends AttributeInfo {
          */
         @Override
         public String jvmTypeName() {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             ClassType parent = getDeclaringClass();
             if (parent != null)
                 sbuf.append(parent.jvmTypeName()).append('$');
@@ -868,7 +868,7 @@ public class SignatureAttribute extends AttributeInfo {
          */
         @Override
         public String toString() {
-            StringBuffer sbuf = new StringBuffer(componentType.toString());
+            StringBuilder sbuf = new StringBuilder(componentType.toString());
             for (int i = 0; i < dim; i++)
                 sbuf.append("[]");
 
diff --git a/src/main/javassist/bytecode/analysis/ControlFlow.java b/src/main/javassist/bytecode/analysis/ControlFlow.java
index e47c00d3..46b82dbf 100644
--- a/src/main/javassist/bytecode/analysis/ControlFlow.java
+++ b/src/main/javassist/bytecode/analysis/ControlFlow.java
@@ -261,13 +261,13 @@ public class ControlFlow {
         }
 
         @Override
-        protected void toString2(StringBuffer sbuf) {
+        protected void toString2(StringBuilder sbuf) {
             super.toString2(sbuf);
             sbuf.append(", incoming{");
             for (int i = 0; i < entrances.length; i++)
                     sbuf.append(entrances[i].position).append(", ");
 
-            sbuf.append("}");
+            sbuf.append('}');
         }
 
         BasicBlock[] getExit() { return exit; }
@@ -360,7 +360,7 @@ public class ControlFlow {
          */
         @Override
         public String toString() {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             sbuf.append("Node[pos=").append(block().position());
             sbuf.append(", parent=");
             sbuf.append(parent == null ? "*" : Integer.toString(parent.block().position()));
diff --git a/src/main/javassist/bytecode/analysis/Frame.java b/src/main/javassist/bytecode/analysis/Frame.java
index 28c62e35..916988c2 100644
--- a/src/main/javassist/bytecode/analysis/Frame.java
+++ b/src/main/javassist/bytecode/analysis/Frame.java
@@ -231,7 +231,7 @@ public class Frame {
 
     @Override
     public String toString() {
-        StringBuffer buffer = new StringBuffer();
+        StringBuilder buffer = new StringBuilder();
 
         buffer.append("locals = [");
         for (int i = 0; i < locals.length; i++) {
@@ -245,7 +245,7 @@ public class Frame {
             if (i < top - 1)
                 buffer.append(", ");
         }
-        buffer.append("]");
+        buffer.append(']');
 
         return buffer.toString();
     }
diff --git a/src/main/javassist/bytecode/analysis/MultiType.java b/src/main/javassist/bytecode/analysis/MultiType.java
index a8f6fc67..90a50843 100644
--- a/src/main/javassist/bytecode/analysis/MultiType.java
+++ b/src/main/javassist/bytecode/analysis/MultiType.java
@@ -312,14 +312,15 @@ public class MultiType extends Type {
         if (resolved != null)
             return resolved.toString();
 
-        StringBuffer buffer = new StringBuffer("{");
+        StringBuilder buffer = new StringBuilder();
+        buffer.append('{');
         for (String key:interfaces.keySet())
             buffer.append(key).append(", ");
         if (potentialClass != null)
-            buffer.append("*").append(potentialClass.toString());
+            buffer.append('*').append(potentialClass.toString());
         else
             buffer.setLength(buffer.length() - 2);
-        buffer.append("}");
+        buffer.append('}');
         return buffer.toString();
     }
 }
diff --git a/src/main/javassist/bytecode/annotation/Annotation.java b/src/main/javassist/bytecode/annotation/Annotation.java
index 1cec468b..f700f036 100644
--- a/src/main/javassist/bytecode/annotation/Annotation.java
+++ b/src/main/javassist/bytecode/annotation/Annotation.java
@@ -210,17 +210,18 @@ public class Annotation {
      */
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer("@");
+        StringBuilder buf = new StringBuilder();
+        buf.append('@');
         buf.append(getTypeName());
         if (members != null) {
-            buf.append("(");
+            buf.append('(');
             for (String name:members.keySet()) {
-                buf.append(name).append("=")
+                buf.append(name).append('=')
                    .append(getMemberValue(name))
                    .append(", ");
             }
             buf.setLength(buf.length()-2);
-            buf.append(")");
+            buf.append(')');
         }
 
         return buf.toString();
diff --git a/src/main/javassist/bytecode/annotation/ArrayMemberValue.java b/src/main/javassist/bytecode/annotation/ArrayMemberValue.java
index d1eeb271..2bf1b7ac 100644
--- a/src/main/javassist/bytecode/annotation/ArrayMemberValue.java
+++ b/src/main/javassist/bytecode/annotation/ArrayMemberValue.java
@@ -117,7 +117,8 @@ public class ArrayMemberValue extends MemberValue {
      */
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer("{");
+        StringBuilder buf = new StringBuilder();
+        buf.append('{');
         if (values != null) {
             for (int i = 0; i < values.length; i++) {
                 buf.append(values[i].toString());
@@ -126,7 +127,7 @@ public class ArrayMemberValue extends MemberValue {
                 }
         }
 
-        buf.append("}");
+        buf.append('}');
         return buf.toString();
     }
 
diff --git a/src/main/javassist/bytecode/annotation/MemberValue.java b/src/main/javassist/bytecode/annotation/MemberValue.java
index da99885c..3eae5355 100644
--- a/src/main/javassist/bytecode/annotation/MemberValue.java
+++ b/src/main/javassist/bytecode/annotation/MemberValue.java
@@ -64,9 +64,9 @@ public abstract class MemberValue {
         int index = classname.indexOf("[]");
         if (index != -1) {
             String rawType = classname.substring(0, index);
-            StringBuffer sb = new StringBuffer(Descriptor.of(rawType));
+            StringBuilder sb = new StringBuilder(Descriptor.of(rawType));
             while (index != -1) {
-                sb.insert(0, "[");
+                sb.insert(0, '[');
                 index = classname.indexOf("[]", index + 1);
             }
             return sb.toString().replace('/', '.');
diff --git a/src/main/javassist/bytecode/stackmap/BasicBlock.java b/src/main/javassist/bytecode/stackmap/BasicBlock.java
index 231ffc3a..2b32a296 100644
--- a/src/main/javassist/bytecode/stackmap/BasicBlock.java
+++ b/src/main/javassist/bytecode/stackmap/BasicBlock.java
@@ -78,33 +78,33 @@ public class BasicBlock {
 
     @Override
     public String toString() {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         String cname = this.getClass().getName();
         int i = cname.lastIndexOf('.');
         sbuf.append(i < 0 ? cname : cname.substring(i + 1));
-        sbuf.append("[");
+        sbuf.append('[');
         toString2(sbuf);
-        sbuf.append("]");
+        sbuf.append(']');
         return sbuf.toString();
     }
 
-    protected void toString2(StringBuffer sbuf) {
+    protected void toString2(StringBuilder sbuf) {
         sbuf.append("pos=").append(position).append(", len=")
             .append(length).append(", in=").append(incoming)
             .append(", exit{");
         if (exit != null)
             for (BasicBlock b:exit)
-                sbuf.append(b.position).append(",");
+                sbuf.append(b.position).append(',');
 
         sbuf.append("}, {");
         Catch th = toCatch;
         while (th != null) {
-            sbuf.append("(").append(th.body.position).append(", ")
+            sbuf.append('(').append(th.body.position).append(", ")
                 .append(th.typeIndex).append("), ");
             th = th.next;
         }
 
-        sbuf.append("}");
+        sbuf.append('}');
     }
 
     /**
diff --git a/src/main/javassist/bytecode/stackmap/TypeData.java b/src/main/javassist/bytecode/stackmap/TypeData.java
index 4762eb85..c676ac79 100644
--- a/src/main/javassist/bytecode/stackmap/TypeData.java
+++ b/src/main/javassist/bytecode/stackmap/TypeData.java
@@ -434,7 +434,7 @@ public abstract class TypeData {
 
         private String fixTypes2(List<TypeData> scc, Set<String> lowersSet, ClassPool cp) throws NotFoundException {
             Iterator<String> it = lowersSet.iterator();
-            if (lowersSet.size() == 0)
+            if (lowersSet.isEmpty())
                 return null;      // only NullType
             else if (lowersSet.size() == 1)
                 return it.next();
diff --git a/src/main/javassist/bytecode/stackmap/TypedBlock.java b/src/main/javassist/bytecode/stackmap/TypedBlock.java
index 14fa7f22..634c8dd0 100644
--- a/src/main/javassist/bytecode/stackmap/TypedBlock.java
+++ b/src/main/javassist/bytecode/stackmap/TypedBlock.java
@@ -59,7 +59,7 @@ public class TypedBlock extends BasicBlock {
     }
 
     @Override
-    protected void toString2(StringBuffer sbuf) {
+    protected void toString2(StringBuilder sbuf) {
         super.toString2(sbuf);
         sbuf.append(",\n stack={");
         printTypes(sbuf, stackTop, stackTypes);
@@ -68,7 +68,7 @@ public class TypedBlock extends BasicBlock {
         sbuf.append('}');
     }
 
-    private void printTypes(StringBuffer sbuf, int size,
+    private void printTypes(StringBuilder sbuf, int size,
                             TypeData[] types) {
         if (types == null)
             return;
diff --git a/src/main/javassist/compiler/CodeGen.java b/src/main/javassist/compiler/CodeGen.java
index 3cb11719..e3115617 100644
--- a/src/main/javassist/compiler/CodeGen.java
+++ b/src/main/javassist/compiler/CodeGen.java
@@ -197,7 +197,7 @@ public abstract class CodeGen extends Visitor implements Opcode, TokenId {
 
         if (dim == 0)
             return name;
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         int d = dim;
         while (d-- > 0)
             sbuf.append('[');
@@ -241,7 +241,7 @@ public abstract class CodeGen extends Visitor implements Opcode, TokenId {
             break;
         }
 
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         while (dim-- > 0)
                 sbuf.append('[');
 
@@ -473,7 +473,7 @@ public abstract class CodeGen extends Visitor implements Opcode, TokenId {
         boolean alwaysBranch = compileBooleanExpr(true, expr);
         if (alwaysBranch) {
             bytecode.addOpcode(Opcode.GOTO);
-            alwaysBranch = breakList.size() == 0;
+            alwaysBranch = breakList.isEmpty();
         }
 
         bytecode.addIndex(pc2 - bytecode.currentPc() + 1);
@@ -1663,7 +1663,7 @@ public abstract class CodeGen extends Visitor implements Opcode, TokenId {
                      * must be passed to Class.forName().
                      */
                     name2 = MemberResolver.jvmToJavaName(name2);
-                    StringBuffer sbuf = new StringBuffer();
+                    StringBuilder sbuf = new StringBuilder();
                     while (i-- >= 0)
                         sbuf.append('[');
 
diff --git a/src/main/javassist/compiler/JvstCodeGen.java b/src/main/javassist/compiler/JvstCodeGen.java
index 5a43d65e..714b9699 100644
--- a/src/main/javassist/compiler/JvstCodeGen.java
+++ b/src/main/javassist/compiler/JvstCodeGen.java
@@ -264,7 +264,7 @@ public class JvstCodeGen extends MemberCodeGen {
     /* To support $cflow().
      */
     protected void atCflow(ASTList cname) throws CompileError {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         if (cname == null || cname.tail() != null)
             throw new CompileError("bad " + cflowName);
 
@@ -288,7 +288,7 @@ public class JvstCodeGen extends MemberCodeGen {
      * <cflow> : $cflow '(' <cflow name> ')'
      * <cflow name> : <identifier> ('.' <identifier>)*
      */
-    private static void makeCflowName(StringBuffer sbuf, ASTree name)
+    private static void makeCflowName(StringBuilder sbuf, ASTree name)
         throws CompileError
     {
         if (name instanceof Symbol) {
diff --git a/src/main/javassist/compiler/Lex.java b/src/main/javassist/compiler/Lex.java
index 498b22fb..b7c39a98 100644
--- a/src/main/javassist/compiler/Lex.java
+++ b/src/main/javassist/compiler/Lex.java
@@ -27,7 +27,7 @@ class Token {
 
 public class Lex implements TokenId {
     private int lastChar;
-    private StringBuffer textBuffer;
+    private StringBuilder textBuffer;
     private Token currentToken;
     private Token lookAheadTokens;
 
@@ -40,7 +40,7 @@ public class Lex implements TokenId {
      */
     public Lex(String s) {
         lastChar = -1;
-        textBuffer = new StringBuffer();
+        textBuffer = new StringBuilder();
         currentToken = new Token();
         lookAheadTokens = null;
 
@@ -123,7 +123,7 @@ public class Lex implements TokenId {
         else if(c == '.'){
             c = getc();
             if ('0' <= c && c <= '9') {
-                StringBuffer tbuf = textBuffer;
+                StringBuilder tbuf = textBuffer;
                 tbuf.setLength(0);
                 tbuf.append('.');
                 return readDouble(tbuf, c, token);
@@ -205,7 +205,7 @@ public class Lex implements TokenId {
 
     private int readStringL(Token token) {
         int c;
-        StringBuffer tbuf = textBuffer;
+        StringBuilder tbuf = textBuffer;
         tbuf.setLength(0);
         for (;;) {
             while ((c = getc()) != '"') {
@@ -287,7 +287,7 @@ public class Lex implements TokenId {
         }
         else if (c2 == 'E' || c2 == 'e'
                  || c2 == 'D' || c2 == 'd' || c2 == '.') {
-            StringBuffer tbuf = textBuffer;
+            StringBuilder tbuf = textBuffer;
             tbuf.setLength(0);
             tbuf.append(value);
             return readDouble(tbuf, c2, token);
@@ -300,7 +300,7 @@ public class Lex implements TokenId {
         }
     }
 
-    private int readDouble(StringBuffer sbuf, int c, Token token) {
+    private int readDouble(StringBuilder sbuf, int c, Token token) {
         if (c != 'E' && c != 'e' && c != 'D' && c != 'd') {
             sbuf.append((char)c);
             for (;;) {
@@ -412,7 +412,7 @@ public class Lex implements TokenId {
     }
 
     private int readIdentifier(int c, Token token) {
-        StringBuffer tbuf = textBuffer;
+        StringBuilder tbuf = textBuffer;
         tbuf.setLength(0);
 
         do {
diff --git a/src/main/javassist/compiler/MemberResolver.java b/src/main/javassist/compiler/MemberResolver.java
index 7fcd5d8a..c01974df 100644
--- a/src/main/javassist/compiler/MemberResolver.java
+++ b/src/main/javassist/compiler/MemberResolver.java
@@ -491,7 +491,7 @@ public class MemberResolver implements TokenId {
                 int i = classname.lastIndexOf('.');
                 if (notCheckInner || i < 0)
                     throw e;
-                StringBuffer sbuf = new StringBuffer(classname);
+                StringBuilder sbuf = new StringBuilder(classname);
                 sbuf.setCharAt(i, '$');
                 classname = sbuf.toString();
             }
diff --git a/src/main/javassist/compiler/Parser.java b/src/main/javassist/compiler/Parser.java
index ae73fb29..2b0dfd69 100644
--- a/src/main/javassist/compiler/Parser.java
+++ b/src/main/javassist/compiler/Parser.java
@@ -1113,7 +1113,7 @@ public final class Parser implements TokenId {
     {
         String cname = toClassName(className);
         if (dim > 0) {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             while (dim-- > 0)
                 sbuf.append('[');
 
@@ -1199,12 +1199,12 @@ public final class Parser implements TokenId {
     private String toClassName(ASTree name)
         throws CompileError
     {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         toClassName(name, sbuf);
         return sbuf.toString();
     }
 
-    private void toClassName(ASTree name, StringBuffer sbuf)
+    private void toClassName(ASTree name, StringBuilder sbuf)
         throws CompileError
     {
         if (name instanceof Symbol) {
diff --git a/src/main/javassist/compiler/TypeChecker.java b/src/main/javassist/compiler/TypeChecker.java
index ec7e3cf3..bceba419 100644
--- a/src/main/javassist/compiler/TypeChecker.java
+++ b/src/main/javassist/compiler/TypeChecker.java
@@ -74,7 +74,7 @@ public class TypeChecker extends Visitor implements Opcode, TokenId {
      */
     protected static String argTypesToString(int[] types, int[] dims,
                                              String[] cnames) {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         sbuf.append('(');
         int n = types.length;
         if (n > 0) {
@@ -96,7 +96,7 @@ public class TypeChecker extends Visitor implements Opcode, TokenId {
      * Converts a tuple of exprType, arrayDim, and className
      * into a String object.
      */
-    protected static StringBuffer typeToString(StringBuffer sbuf,
+    protected static StringBuilder typeToString(StringBuilder sbuf,
                                         int type, int dim, String cname) {
         String s;
         if (type == CLASS)
diff --git a/src/main/javassist/compiler/ast/ASTList.java b/src/main/javassist/compiler/ast/ASTList.java
index 67fbd97a..d9232ca0 100644
--- a/src/main/javassist/compiler/ast/ASTList.java
+++ b/src/main/javassist/compiler/ast/ASTList.java
@@ -79,7 +79,7 @@ public class ASTList extends ASTree {
 
     @Override
     public String toString() {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         sbuf.append("(<");
         sbuf.append(getTag());
         sbuf.append('>');
diff --git a/src/main/javassist/compiler/ast/ASTree.java b/src/main/javassist/compiler/ast/ASTree.java
index 7fd05fd4..3d4dd842 100644
--- a/src/main/javassist/compiler/ast/ASTree.java
+++ b/src/main/javassist/compiler/ast/ASTree.java
@@ -46,7 +46,7 @@ public abstract class ASTree implements Serializable {
 
     @Override
     public String toString() {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         sbuf.append('<');
         sbuf.append(getTag());
         sbuf.append('>');
diff --git a/src/main/javassist/compiler/ast/Declarator.java b/src/main/javassist/compiler/ast/Declarator.java
index 24170db0..c29f6740 100644
--- a/src/main/javassist/compiler/ast/Declarator.java
+++ b/src/main/javassist/compiler/ast/Declarator.java
@@ -107,12 +107,12 @@ public class Declarator extends ASTList implements TokenId {
         if (name == null)
             return null;
 
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         astToClassName(sbuf, name, sep);
         return sbuf.toString();
     }
 
-    private static void astToClassName(StringBuffer sbuf, ASTList name,
+    private static void astToClassName(StringBuilder sbuf, ASTList name,
                                        char sep) {
         for (;;) {
             ASTree h = name.head();
diff --git a/src/main/javassist/compiler/ast/Pair.java b/src/main/javassist/compiler/ast/Pair.java
index 840c1145..949028a4 100644
--- a/src/main/javassist/compiler/ast/Pair.java
+++ b/src/main/javassist/compiler/ast/Pair.java
@@ -37,7 +37,7 @@ public class Pair extends ASTree {
 
     @Override
     public String toString() {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         sbuf.append("(<Pair> ");
         sbuf.append(left == null ? "<null>" : left.toString());
         sbuf.append(" . ");
diff --git a/src/main/javassist/convert/TransformAccessArrayField.java b/src/main/javassist/convert/TransformAccessArrayField.java
index 6dab42a5..b80ed0c3 100644
--- a/src/main/javassist/convert/TransformAccessArrayField.java
+++ b/src/main/javassist/convert/TransformAccessArrayField.java
@@ -218,7 +218,7 @@ public final class TransformAccessArrayField extends Transformer {
             break;
         }
 
-        if (methodName.equals(""))
+        if ("".equals(methodName))
             methodName = null;
 
         return methodName;
diff --git a/src/main/javassist/tools/rmi/StubGenerator.java b/src/main/javassist/tools/rmi/StubGenerator.java
index b0817ab5..a06ebc60 100644
--- a/src/main/javassist/tools/rmi/StubGenerator.java
+++ b/src/main/javassist/tools/rmi/StubGenerator.java
@@ -183,7 +183,7 @@ public class StubGenerator implements Translator {
         if (!rtclass.isArray())
             name = rtclass.getName();
         else {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             do {
                 sbuf.append("[]");
                 rtclass = rtclass.getComponentType();
diff --git a/src/main/javassist/tools/web/Webserver.java b/src/main/javassist/tools/web/Webserver.java
index d90e8e34..99e15faf 100644
--- a/src/main/javassist/tools/web/Webserver.java
+++ b/src/main/javassist/tools/web/Webserver.java
@@ -222,7 +222,7 @@ public class Webserver {
     }
 
     private String readLine(InputStream in) throws IOException {
-        StringBuffer buf = new StringBuffer();
+        StringBuilder buf = new StringBuilder();
         int c;
         while ((c = in.read()) >= 0 && c != 0x0d)
             buf.append((char)c);
diff --git a/src/main/javassist/util/proxy/ProxyFactory.java b/src/main/javassist/util/proxy/ProxyFactory.java
index 7d88e07a..2a20b2ca 100644
--- a/src/main/javassist/util/proxy/ProxyFactory.java
+++ b/src/main/javassist/util/proxy/ProxyFactory.java
@@ -576,14 +576,14 @@ public class ProxyFactory {
 
     public String getKey(Class<?> superClass, Class<?>[] interfaces, byte[] signature, boolean useWriteReplace)
     {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         if (superClass != null){
             sbuf.append(superClass.getName());
         }
-        sbuf.append(":");
+        sbuf.append(':');
         for (int i = 0; i < interfaces.length; i++) {
             sbuf.append(interfaces[i].getName());
-            sbuf.append(":");
+            sbuf.append(':');
         }
         for (int i = 0; i < signature.length; i++) {
             byte b = signature[i];
diff --git a/src/main/javassist/util/proxy/RuntimeSupport.java b/src/main/javassist/util/proxy/RuntimeSupport.java
index 0bd0cce9..9eb1c49e 100644
--- a/src/main/javassist/util/proxy/RuntimeSupport.java
+++ b/src/main/javassist/util/proxy/RuntimeSupport.java
@@ -198,7 +198,7 @@ public class RuntimeSupport {
      * @param retType   return type.
      */
     public static String makeDescriptor(Class<?>[] params, Class<?> retType) {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         sbuf.append('(');
         for (int i = 0; i < params.length; i++)
             makeDesc(sbuf, params[i]);
@@ -217,12 +217,12 @@ public class RuntimeSupport {
      * @param retType   return type.
      */
     public static String makeDescriptor(String params, Class<?> retType) {
-        StringBuffer sbuf = new StringBuffer(params);
+        StringBuilder sbuf = new StringBuilder(params);
         makeDesc(sbuf, retType);
         return sbuf.toString();
     }
 
-    private static void makeDesc(StringBuffer sbuf, Class<?> type) {
+    private static void makeDesc(StringBuilder sbuf, Class<?> type) {
         if (type.isArray()) {
             sbuf.append('[');
             makeDesc(sbuf, type.getComponentType());