Remove system property for stable lambda class names. Remove the test.

Author: sstanoje

src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java

@@ -32,14 +32,11 @@
 import sun.invoke.util.VerifyAccess;
 import sun.security.action.GetBooleanAction;
 
-import java.nio.charset.StandardCharsets;
 import java.io.Serializable;
 import java.lang.constant.ConstantDescs;
 import java.lang.reflect.Modifier;
 import java.util.LinkedHashSet;
 import java.util.Set;
-import java.util.StringJoiner;
-import java.util.zip.CRC32;
 
 import static java.lang.invoke.MethodHandleStatics.CLASSFILE_VERSION;
 import static java.lang.invoke.MethodHandles.Lookup.ClassOption.NESTMATE;
@@ -87,11 +84,6 @@
 
     private static final boolean disableEagerInitialization;
 
-    private static final boolean generateStableLambdaNames;
-
-    private static final int mask1 = 0b10101010;
-    private static final int mask2 = 0b01010101;
-
     // condy to load implMethod from class data
     private static final ConstantDynamic implMethodCondy;
 
@@ -105,9 +97,6 @@
         final String disableEagerInitializationKey = "jdk.internal.lambda.disableEagerInitialization";
         disableEagerInitialization = GetBooleanAction.privilegedGetProperty(disableEagerInitializationKey);
 
-        final String generateStableLambdaNamesKey = "jdk.internal.lambda.generateStableLambdaNames";
-        generateStableLambdaNames = GetBooleanAction.privilegedGetProperty(generateStableLambdaNamesKey);
-
         // condy to load implMethod from class data
         MethodType classDataMType = methodType(Object.class, MethodHandles.Lookup.class, String.class, Class.class);
         Handle classDataBsm = new Handle(H_INVOKESTATIC, Type.getInternalName(MethodHandles.class), "classData",
@@ -183,7 +172,7 @@ public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
         implMethodName = implInfo.getName();
         implMethodDesc = implInfo.getMethodType().toMethodDescriptorString();
         constructorType = factoryType.changeReturnType(Void.TYPE);
-        lambdaClassName = generateStableLambdaNames ? stableLambdaClassName(targetClass) : lambdaClassName(targetClass);
+        lambdaClassName = lambdaClassName(targetClass);
         // If the target class invokes a protected method inherited from a
         // superclass in a different package, or does 'invokespecial', the
         // lambda class has no access to the resolved method. Instead, we need
@@ -208,10 +197,6 @@ public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
     }
 
     private static String lambdaClassName(Class<?> targetClass) {
-        return createNameFromTargetClass(targetClass);
-    }
-
-    private static String createNameFromTargetClass(Class<?> targetClass) {
         String name = targetClass.getName();
         if (targetClass.isHidden()) {
             // use the original class name
@@ -220,78 +205,6 @@ private static String createNameFromTargetClass(Class<?> targetClass) {
         return name.replace('.', '/') + "$$Lambda";
     }
 
-    /**
-     * Create a stable name for the lambda class.
-     * When CDS archiving is enabled, lambda classes
-     * are stored in the archive using some parameters from
-     * the InnerClassLambdaMetafactory. To distinguish between
-     * two lambdas, even when CDS archiving is disabled,
-     * use a superset of those parameters to create a stable name.
-     *
-     * Concatenate all the parameters chosen for the stable name,
-     * and hash them into 64-bit hash value.
-     * Any additional changes to this method will result in unstable
-     * hash values across different versions. Thus, every change
-     * to this method should be regarded as a backward incompatible change.
-     *
-     * No matter what hash function we use, there is a possibility of
-     * collisions in names. We expect a relatively low number of lambdas
-     * per class. Thus, we don't expect to have collisions using the described
-     * hash function. Every tool that uses this feature should handle potential
-     * collisions on its own. There is no guarantee that names will be unique,
-     * only that they will be stable (identical in every run).
-     *
-     * @return a stable name for the created lambda class.
-     */
-    private String stableLambdaClassName(Class<?> targetClass) {
-        String name = createNameFromTargetClass(targetClass);
-
-        StringBuilder hashData1 = new StringBuilder(), hashData2 = new StringBuilder();
-        appendData(hashData1, hashData2, interfaceMethodName);
-        appendData(hashData1, hashData2, getQualifiedSignature(factoryType));
-        appendData(hashData1, hashData2, getQualifiedSignature(interfaceMethodType));
-        appendData(hashData1, hashData2, implementation.internalMemberName().toString());
-        appendData(hashData1, hashData2, getQualifiedSignature(dynamicMethodType));
-
-        for (Class<?> clazz : altInterfaces) {
-            appendData(hashData1, hashData2, clazz.getName());
-        }
-
-        for (MethodType method : altMethods) {
-            appendData(hashData1, hashData2, getQualifiedSignature(method));
-        }
-
-        return name + hashToHexString(hashData1.toString(), hashData2.toString());
-    }
-
-    private void appendData(StringBuilder hashData1, StringBuilder hashData2, String data) {
-        for (int i = 0; i < data.length(); i++) {
-            hashData1.append((char)(data.charAt(i) & mask1));
-            hashData2.append((char)(data.charAt(i) & mask2));
-        }
-    }
-
-    private long hashStringToLong(String hashData) {
-        CRC32 crc32 = new CRC32();
-        crc32.update(hashData.getBytes(StandardCharsets.UTF_8));
-        return crc32.getValue();
-    }
-
-    private String hashToHexString(String hashData1, String hashData2) {
-        long hashValueData1 = hashStringToLong(hashData1);
-        long hashValueData2 = hashStringToLong(hashData2);
-        return Long.toHexString(hashValueData1 | (hashValueData2 << 32));
-    }
-
-    private String getQualifiedSignature(MethodType type) {
-        StringJoiner sj = new StringJoiner(",", "(", ")" + type.returnType().getName());
-        Class<?>[] ptypes = type.ptypes();
-        for (int i = 0; i < ptypes.length; i++) {
-            sj.add(ptypes[i].getName());
-        }
-        return sj.toString();
-    }
-
     /**
      * Build the CallSite. Generate a class file which implements the functional
      * interface, define the class, if there are no parameters create an instance