The following exception is thrown while executing the test case below.

java.lang.ClassCastException: com.sun.tools.javac.code.Symbol$TypeSymbol cannot be cast to com.sun.tools.javac.code.Symbol$ClassSymbol
	at com.sun.tools.javac.comp.Check.checkImplementations(Check.java:1558)
	at com.sun.tools.javac.comp.Check.checkImplementations(Check.java:1549)
	at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:2736)
	at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2666)
	at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2602)
	at com.sun.tools.javac.comp.Attr.attribBounds(Attr.java:480)
	at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:584)
	at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:653)
	at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:372)
	at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:409)
	at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:2740)
	at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2666)
	at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2602)
	at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1050)
	at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1026)
	at com.sun.tools.javac.api.JavacTaskImpl.analyze(JavacTaskImpl.java:369)
	at com.sun.tools.javac.api.JavacTaskImpl.analyze(JavacTaskImpl.java:349)
	at T9999999.main(T9999999.java:61)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.sun.javatest.regtest.MainAction$SameVMThread.run(MainAction.java:560)
	at java.lang.Thread.run(Thread.java:619)


/*
 * @test 
 * @bug 9999999
 * @summary a ClassCastException thrown when analyzing incorrect code.
 */

import com.sun.source.util.JavacTask;
import java.io.IOException;
import java.net.URI;
import java.util.Arrays;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.ToolProvider;

public class T9999999 {
    static class MyFileObject extends SimpleJavaFileObject {
        private String text;
        public MyFileObject(String text) {
            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
            this.text = text;
        }
        @Override
        public CharSequence getCharContent(boolean ignoreEncodingErrors) {
            return text;
        }
    }
    
    public static void main(String[] args) throws IOException {
        final String bootPath = System.getProperty("sun.boot.class.path"); //NOI18N
        final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
        assert tool != null;
        
        String code = "package test; public class Test<S> { <T extends S & Runnable> void test() {} }";
        
        JavacTask ct = (JavacTask)tool.getTask(null, null, null, Arrays.asList("-bootclasspath",  bootPath, "-Xjcov"), null, Arrays.asList(new MyFileObject(code)));
        
        ct.analyze();
    }
}


I have a revision 252 from:
https://openjdk.dev.java.net/svn/openjdk/jdk/trunk

See also NetBeans issue:
http://www.netbeans.org/issues/show_bug.cgi?id=116436
An error is (correctly) reported before the exception occurs (the error is that the bound combines a type variable and an interface, which is prohibited, according to JLS 4.4). The problem IMO is that the Attr/Check are not prepared for this situation. Presumably because the execution never reaches Attr/Check in the cmd line javac in this case.