Revert "Fix byte array memory leak from MemoryBasedClassLoader"

This reverts commit 58b033d9fb.

compiler/preloader/src/org/jetbrains/kotlin/preloading/ClassPreloadingUtils.java

@@ -17,8 +17,6 @@
 package org.jetbrains.kotlin.preloading;
 
 import java.io.*;
-import java.net.URL;
-import java.net.URLClassLoader;
 import java.util.*;
 import java.util.jar.Attributes;
 import java.util.jar.JarFile;
@@ -31,6 +29,8 @@ public class ClassPreloadingUtils {
     /**
      * Creates a class loader that loads all classes from {@code jarFiles} into memory to make loading faster (avoid skipping through zip archives).
      *
+     * NOTE: if many resources with the same name exist, only the first one will be loaded
+     *
      * @param jarFiles jars to load all classes from
      * @param classCountEstimation an estimated number of classes in a the jars
      * @param parentClassLoader parent class loader
@@ -53,15 +53,7 @@ public class ClassPreloadingUtils {
             parentClassLoader = preloadClasses(classpath, classCountEstimation, parentClassLoader, null, handler);
         }
 
-        return new MemoryBasedClassLoader(classesToLoadByParent, createFallbackClassLoader(jarFiles, parentClassLoader), entries, handler);
-    }
-
-    private static URLClassLoader createFallbackClassLoader(Collection<File> files, ClassLoader parent) throws IOException {
-        List<URL> urls = new ArrayList<URL>(files.size());
-        for (File file : files) {
-            urls.add(file.toURI().toURL());
-        }
-        return new URLClassLoader(urls.toArray(new URL[urls.size()]), parent);
+        return new MemoryBasedClassLoader(classesToLoadByParent, parentClassLoader, entries, handler);
     }
 
     public static ClassLoader preloadClasses(

compiler/preloader/src/org/jetbrains/kotlin/preloading/MemoryBasedClassLoader.java

@@ -21,14 +21,6 @@ import java.net.URL;
 import java.util.*;
 
 @SuppressWarnings("unchecked")
-/**
- * A class loader which loads classes and resources from the given map.
- *
- * To save memory, as soon as any class is loaded, its bytecode is removed from the map.
- * This means that once any class is loaded, it _cannot be found_ as a resource anymore.
- * Therefore if you need to be able to find classes via findResource(), you should pass a parent
- * class loader which is able to do that at any point of time.
- */
 public class MemoryBasedClassLoader extends ClassLoader {
     private final ClassCondition classesToLoadByParent;
     private final ClassLoader parent;
@@ -85,9 +77,6 @@ public class MemoryBasedClassLoader extends ClassLoader {
         Object resources = preloadedResources.get(internalName);
         if (resources == null) return null;
 
-        // Clear the resource, we won't need it anymore
-        preloadedResources.remove(internalName);
-
         ResourceData resourceData = resources instanceof ResourceData
                                     ? ((ResourceData) resources)
                                     : ((List<ResourceData>) resources).get(0);

compiler/util/src/org/jetbrains/kotlin/utils/PathUtil.java

@@ -135,11 +135,7 @@ public class PathUtil {
 
     @NotNull
     public static File getResourcePathForClass(@NotNull Class aClass) {
-        String path = "/" + aClass.getName().replace('.', '/') + ".class";
-        String resourceRoot = PathManager.getResourceRoot(aClass, path);
-        if (resourceRoot == null) {
-            throw new IllegalStateException("Resource not found: " + path);
-        }
+        String resourceRoot = PathManager.getResourceRoot(aClass, "/" + aClass.getName().replace('.', '/') + ".class");
         return new File(resourceRoot).getAbsoluteFile();
     }