Type erasure

>> output result

> javac *.java
> javap -c StringBuilderProcessor

Compiled from "StringBuilderProcessor.java"
public class StringBuilderProcessor implements GenericProcessor<java.lang.StringBuilder> {
  public StringBuilderProcessor();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public void modify(java.lang.StringBuilder);
    Code:
       0: aload_1
       1: ldc           #2                  // String test
       3: invokevirtual #3                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;

       6: pop
       7: return

  public void modify(java.lang.Object);
    Code:
       0: aload_0
       1: aload_1
       2: checkcast     #4                  // class java/lang/StringBuilder
       5: invokevirtual #5                  // Method modify:(Ljava/lang/StringBuilder;)V
       8: return
}

> javap -c MainTest

Compiled from "MainTest.java"
public class MainTest {
  public MainTest();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public static void main(java.lang.String[]);
    Code:
       0: new           #2                  // class StringBuilderProcessor
       3: dup
       4: invokespecial #3                  // Method StringBuilderProcessor."<init>":()V
       7: astore_1
       8: aload_1
       9: new           #4                  // class java/lang/StringBuilder
      12: dup
      13: invokespecial #5                  // Method java/lang/StringBuilder."<init>":()V
      16: invokeinterface #6,  2            // InterfaceMethod GenericProcessor.modify:(Ljava/lang/Object;)V
      21: return
}

GenericProcessor.java

public interface GenericProcessor<T> {

    void modify(T test);
}

MainTest.java

public class MainTest {
    public static void main(String[] args) {
        GenericProcessor p = new StringBuilderProcessor();
        p.modify(new StringBuilder());
    }
}

StringBuilderProcessor.java

public class StringBuilderProcessor implements GenericProcessor<StringBuilder> {

    @Override
    public void modify(StringBuilder test) {
        test.append("test");
    }
}