630111 - Codegen optimizer fails with Unsupported major.minor version 0.0 on JDK7

Status: RESOLVED FIXED

(Rhino Graveyard :: Compiler, defect)

Description

[Bruno Fernandez-Ruiz]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_6; en-us) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4
Build Identifier: CVS HEAD

When setting ctx.setOptimizationLevel(9) to force compilation, generated class files under JDK7 b127 have major.minor version 0.0 and fail to load.

Reproducible: Always

Steps to Reproduce:
Execute test code:

        ContextFactory contextFactory = ContextFactory.getGlobal();
        contextFactory.call(new ContextAction() {
            @Override
            public Object run(Context ctx) {
                ScriptableObject scope = ctx.initStandardObjects(null, true);
                ctx.setOptimizationLevel(9);
                return ctx.evaluateString(scope, "var h = 'test'", "test", 0, null);
            }
        });
Actual Results:  
java.lang.UnsupportedClassVersionError: org/mozilla/javascript/gen/test_1 : Unsupported major.minor version 0.0
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:795)
	at org.mozilla.javascript.DefiningClassLoader.defineClass(DefiningClassLoader.java:62)
	at org.mozilla.javascript.optimizer.Codegen.defineClass(Codegen.java:160)
	at org.mozilla.javascript.optimizer.Codegen.createScriptObject(Codegen.java:115)
	at org.mozilla.javascript.Context.compileImpl(Context.java:2442)
	at org.mozilla.javascript.Context.compileString(Context.java:1367)
	at org.mozilla.javascript.Context.compileString(Context.java:1356)
	at org.mozilla.javascript.Context.evaluateString(Context.java:1108)
	at nodus.js.JdkBug$1.run(JdkBug.java:37)

Expected Results:  
finish without an error

java version "1.7.0-ea"
Java(TM) SE Runtime Environment (build 1.7.0-ea-b127)
Java HotSpot(TM) Client VM (build 20.0-b06, mixed mode, sharing)

openjdk version "1.7.0-internal"
OpenJDK Runtime Environment (build 1.7.0-internal-b00)
OpenJDK 64-Bit Server VM (build 20.0-b06, mixed mode)

Comment 1

[Bruno Fernandez-Ruiz]

Attachment: Determine major.minor version using java.lang.Object.class

Instead of using ClassFileWriter.class to determine the major.minor version, we can use java/lang/Object.class since the runtime that loaded it should be able to load a generated class.

Comment 2

[Hannes Wallnoefer]

Turns out the problem was due to InputStream.read() on the class resource only reading two bytes the first time around. Fixed in CVS.