improves the backward compatibility of LoaderClassPath.rel_3_21_0-java9-ea2

LoaderClassPath is modified to show the same behavior in both Java 8 and 9.

1 files changed, 44 insertions, 5 deletions

diff --git a/src/main/javassist/LoaderClassPath.java b/src/main/javassist/LoaderClassPath.java
index d516323e..daf43c20 100644
--- a/src/main/javassist/LoaderClassPath.java
+++ b/src/main/javassist/LoaderClassPath.java
@@ -48,10 +48,39 @@ public class LoaderClassPath implements ClassPath {
     private WeakReference clref;
 
     /**
+     * If true, this search path implicitly includes
+     * a {@code ModuleClassPath} as a fallback.
+     * For backward compatibility, this field is set to true
+     * if the JVM is Java 9 or later.  It can be false in
+     * Java 9 but the behavior of {@code LoadClassPath} will
+     * be different from its behavior in Java 8 or older.
+     *
+     * <p>This field must be false if the JVM is Java 8 or older.
+     *
+     * @since 3.21
+     */
+    public static boolean fallbackOnModuleClassPath
+        = javassist.bytecode.ClassFile.MAJOR_VERSION >= javassist.bytecode.ClassFile.JAVA_9;
+
+    private static ModuleClassPath moduleClassPath = null;
+
+    private boolean doFallback;
+
+    /**
      * Creates a search path representing a class loader.
      */
     public LoaderClassPath(ClassLoader cl) {
+        this(cl, fallbackOnModuleClassPath);
+    }
+
+    LoaderClassPath(ClassLoader cl, boolean fallback) {
         clref = new WeakReference(cl);
+        doFallback = fallback;
+        if (fallback)
+            synchronized (LoaderClassPath.class) {
+                if (moduleClassPath == null)
+                    moduleClassPath = new ModuleClassPath();
+            }
     }
 
     public String toString() {
@@ -67,13 +96,18 @@ public class LoaderClassPath implements ClassPath {
      * This method calls <code>getResourceAsStream(String)</code>
      * on the class loader.
      */
-    public InputStream openClassfile(String classname) {
+    public InputStream openClassfile(String classname) throws NotFoundException {
         String cname = classname.replace('.', '/') + ".class";
         ClassLoader cl = (ClassLoader)clref.get();
         if (cl == null)
             return null;        // not found
-        else
-            return cl.getResourceAsStream(cname);
+        else {
+            InputStream is = cl.getResourceAsStream(cname);
+            if (is == null && doFallback)
+                return moduleClassPath.openClassfile(classname);
+            else
+                return is;
+        }
     }
 
     /**
@@ -88,8 +122,13 @@ public class LoaderClassPath implements ClassPath {
         ClassLoader cl = (ClassLoader)clref.get();
         if (cl == null)
             return null;        // not found
-        else
-            return cl.getResource(cname);
+        else {
+            URL url = cl.getResource(cname);
+            if (url == null && doFallback)
+                return moduleClassPath.find(classname);
+            else
+                return url;
+        }
     }
 
     /**