gistfile1.txt

public class GenericTest {

  public static <T extends java.lang.Number> T test(java.lang.Object);
    Code:
       0: aload_0
       1: checkcast     #18                 // class java/lang/Number
       4: areturn

  public static void test();
    Code:
       0: iconst_1
       1: invokestatic  #22                 // Method java/lang/Integer.valueOf:(I)Ljava/lang/Integer;
       4: invokestatic  #28                 // Method test:(Ljava/lang/Object;)Ljava/lang/Number;
       7: checkcast     #23                 // class java/lang/Integer
      10: astore_0
      11: getstatic     #30                 // Field java/lang/System.out:Ljava/io/PrintStream;
      14: aload_0
      15: invokevirtual #36                 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
      18: return
}

gistfile2.java

public class GenericTest {

    @SuppressWarnings("unchecked")
    public static <T extends Number> T test(Object i) {
        return (T)i;
    }
    
    public static void test() {
        Integer i = test(1);
        System.out.println(i);
    }
    
}