optimizations: working with Abraham on these: this one avoids trailing ':' which will create a CP hit more frequently.

weaver/src/org/aspectj/weaver/bcel/LazyClassGen.java

 		if (types == null) {
 			return "";
 		}
-		StringBuffer buf = new StringBuffer();
+		StringBuilder buf = new StringBuilder();
 		for (int i = 0, len = types.length; i < len; i++) {
+			if (i > 0) {
+				buf.append(':');
+			}
 			buf.append(makeString(types[i]));
-			buf.append(':');
 		}
 		return buf.toString();
 	}
 		if (names == null) {
 			return "";
 		}
-		StringBuffer buf = new StringBuffer();
+		StringBuilder buf = new StringBuilder();
 		for (int i = 0, len = names.length; i < len; i++) {
+			if (i > 0) {
+				buf.append(':');
+			}
 			buf.append(names[i]);
-			buf.append(':');
 		}
 		return buf.toString();
 	}

weaver/testdata/StaticEnclosingTjpBeforeHelloWorld.txt

                     LDC "9"
                     LDC "main"
                     LDC "HelloWorld"
-                    LDC "[Ljava.lang.String;:"
-                    LDC "args:"
+                    LDC "[Ljava.lang.String;"
+                    LDC "args"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;

weaver/testdata/StaticTjpBeforeHelloWorld.txt

                     LDC "1"
                     LDC "println"
                     LDC "java.io.PrintStream"
-                    LDC "java.lang.String:"
-                    LDC "arg0:"
+                    LDC "java.lang.String"
+                    LDC "arg0"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;
                     LDC "9"
                     LDC "main"
                     LDC "HelloWorld"
-                    LDC "[Ljava.lang.String;:"
-                    LDC "args:"
+                    LDC "[Ljava.lang.String;"
+                    LDC "args"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;

weaver/testdata/TjpAround2HelloWorld.txt

                     LDC "1"
                     LDC "println"
                     LDC "java.io.PrintStream"
-                    LDC "java.lang.String:"
-                    LDC "arg0:"
+                    LDC "java.lang.String"
+                    LDC "arg0"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;
                     LDC "9"
                     LDC "main"
                     LDC "HelloWorld"
-                    LDC "[Ljava.lang.String;:"
-                    LDC "args:"
+                    LDC "[Ljava.lang.String;"
+                    LDC "args"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;

weaver/testdata/TjpAroundHelloWorld.txt

                     LDC "1"
                     LDC "println"
                     LDC "java.io.PrintStream"
-                    LDC "java.lang.String:"
-                    LDC "arg0:"
+                    LDC "java.lang.String"
+                    LDC "arg0"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;
                     LDC "9"
                     LDC "main"
                     LDC "HelloWorld"
-                    LDC "[Ljava.lang.String;:"
-                    LDC "args:"
+                    LDC "[Ljava.lang.String;"
+                    LDC "args"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;

weaver/testdata/TjpBeforeHelloWorld.txt

                     LDC "1"
                     LDC "println"
                     LDC "java.io.PrintStream"
-                    LDC "java.lang.String:"
-                    LDC "arg0:"
+                    LDC "java.lang.String"
+                    LDC "arg0"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;
                     LDC "9"
                     LDC "main"
                     LDC "HelloWorld"
-                    LDC "[Ljava.lang.String;:"
-                    LDC "args:"
+                    LDC "[Ljava.lang.String;"
+                    LDC "args"
                     LDC ""
                     LDC "void"
                     INVOKEVIRTUAL org.aspectj.runtime.reflect.Factory.makeMethodSig (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/MethodSignature;