jdk 编译器 对final字段的处理

class FinalTest{

    void a(){

        final int i=10;

        int j=10;

    }

}

           stack=2, locals=3, args_size=1

　　　　　　// 这个地方，应该有i的赋值？

         0: bipush        10
         2: istore_2     

         3: return        

class FinalTest{

    void a(){

        int i=10;

        int j=10;

    }

}

     stack=2, locals=3, args_size=1

         0: bipush        10
         2: istore_1     
         3: bipush        10
         5: istore_2     

         6: return        

--------------------------------------------------------------------------------------------

class FinalTest{

    void a(){

        int i=10;

        int j=10;

        b(i);

        b(j);

    }

    void b(int i){

 

    }

}

     stack=2, locals=3, args_size=1

         0: bipush        10

         2: istore_1     
         3: bipush        10
         5: istore_2     
         6: aload_0      
         7: iload_1      
         8: invokevirtual #2                  // Method b:(I)V
        11: aload_0      
        12: iload_2      
        13: invokevirtual #2                  // Method b:(I)V

        16: return   

class FinalTest{

    void a(){

        final int i=10;

        int j=10;

        b(i);

        b(j);

    }

    void b(int i){

 

    }

}

      stack=2, locals=3, args_size=1
         0: bipush        10
         2: istore_2     
         3: aload_0    

　　　　　　// 直接将10入操作数栈，而不在通过i 
         4: bipush        10
         6: invokevirtual #2                  // Method b:(I)V
         9: aload_0      
        10: iload_2      
        11: invokevirtual #2                  // Method b:(I)V

        14: return       

  

--------------------------------------------------------------------------------------------

// object加不加final一个样

class FinalTest{

    void a(){

        final Object o=new Object();

        Object o1=new Object();

    }

}

 

class FinalTest{

    void a(){

        Object o=new Object();

        Object o1=new Object();

    }

}

 

         0: new           #2                  // class java/lang/Object
         3: dup          
         4: invokespecial #1                  // Method java/lang/Object."<init>":()V
         7: astore_1     
         8: new           #2                  // class java/lang/Object
        11: dup          
        12: invokespecial #1                  // Method java/lang/Object."<init>":()V
        15: astore_2     

        16: return  

--------------------------------------------------------------------------------------------     

// 支持字面量的Object类型--String

class FinalTest{

    void a(){

        final String s1="a";

        String s2="a";

    }

}   

         // 同int一样

         0: ldc           #2                  // String a

         2: astore_2     

         3: return  

class FinalTest{

    void a(){

        String s1="a";

        String s2="a";

    }

}

0: ldc           #2                  // String a
         2: astore_1     
         3: ldc           #2                  // String a
         5: astore_2     

         6: return      

 // 最后，如果有调用的情况，应该和INT型的处理是一样的