Take one very simple class, compile it and process it with ASMifier and
guess what?
Classes that implement functional interfaces are compiled to contain
synthetic bridge methods that check Generic type casts!
In other news I'm still waiting for a Jenkins run to complete without
someone aborting it early, I've asked on infrastructure if they can
limit who can abort running tests to those who created them or Jenkins
administrators.
public class ConsumerTest1 implements Consumer<String> {
@Override
public void accept(String t) {
System.out.println(t);
}
}
package asm.testing;
import java.util.*;
import org.objectweb.asm.*;
import org.objectweb.asm.attrs.*;
public class ConsumerTest1Dump implements Opcodes {
public static byte[] dump () throws Exception {
ClassWriter cw = new ClassWriter(0);
FieldVisitor fv;
MethodVisitor mv;
AnnotationVisitor av0;
cw.visit(52, ACC_PUBLIC + ACC_SUPER, "testing/ConsumerTest1",
"Ljava/lang/Object;Ljava/util/function/Consumer<Ljava/lang
/String;>;", "java/lang/Object", new String[] {
"java/util/function/Consumer" });
{
mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V",
false);
mv.visitInsn(RETURN);
mv.visitMaxs(1, 1);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "accept", "(Ljava/lang/String;)V", null,
null);
mv.visitCode();
mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out",
"Ljava/io/PrintStream;");
mv.visitVarInsn(ALOAD, 1);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println",
"(Ljava/lang/String;)V", false);
mv.visitInsn(RETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC + ACC_BRIDGE + ACC_SYNTHETIC, "accept",
"(Ljava/lang/Object;)V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, "java/lang/String");
mv.visitMethodInsn(INVOKEVIRTUAL, "testing/ConsumerTest1", "accept",
"(Ljava/lang/String;)V", false);
mv.visitInsn(RETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
cw.visitEnd();
return cw.toByteArray();
}
}
