Geek Answers Handbook

Java: determining compilation time and the “most specific method”

Overloaded functions compute1(), compute2()and compute5()cause compilation errors if you try to use them below:

package com.example.test.reflect;

class JLS15Test2
{
    int compute1(Object o1, Integer i, Integer j)         { return 1; }
    int compute1(String s1, Integer i, int j)             { return 2; }

    int compute2(Object o1, Integer i, int j)             { return 3; }
    int compute2(String s1, Integer i, Integer j)         { return 4; }

    int compute3(Object o1, Integer i, int j)             { return 5; }
    int compute3(String s1, Integer i, int j)             { return 6; }

    int compute4(Object o1, Integer i, Integer j)         { return 7; }
    int compute4(String s1, Integer i, Integer j)         { return 8; }

    int compute5(Object o1, Integer i, Object j)          { return 9; }
    int compute5(String s1, Integer i, int j)             { return 10; }


    public static void main(String[] args) 
    {
        JLS15Test2 y = new JLS15Test2();

        // won't compile:
        // The method compute1(Object, Integer, Integer) is ambiguous 
        // for the type JLS15Test2
        // System.out.println(y.compute1("hi", 1, 1));

        // Neither will this (same reason)
        // System.out.println(y.compute2("hi", 1, 1));
        System.out.println(y.compute3("hi", 1, 1));
        System.out.println(y.compute4("hi", 1, 1));

        // neither will this (same reason)
        // System.out.println(y.compute5("hi", 1, 1));
    }
}

15.12 JLS, , ... 2 ( /unboxing, varargs) " " JLS ( ) , , (, int Integer) . , Integer Integer, int int, Integer int w/r/t, compute1()/compute2() .

( compute3() compute4() String , Object, 6 8.)

?

+5
2

, .

0

, int Integer, , :

int compute6(int i) { return 11;}
int compute6(Integer i){return 12;}
...
System.out.println(y.compute6(1));

, , - , .

0

More articles:


All Articles