Poll: Kiểm tra kiến thức Core Java (Garbage Collection )- 1.08

[qtd (Đỗ Trung Quân)]

After line 8 runs. how many objects are eligible for garbage collection?

public class X 
{
    public static void main(String [] args) 
    {
        X x = new X();
        X x2 = m1(x); /* Line 6 */
        X x4 = new X();
        x2 = x4; /* Line 8 */
        doComplexStuff();
    }
    static X m1(X mx) 
    {
        mx = new X();
        return mx;
    }
}

• A. 0
• B. 1
• C. 2
• D. 3

Answer:

Option B

[details=Explaintion]By the time line 8 has run, the only object without a reference is the one generated as a result of line 6. Remember that “Java is pass by value,” so the reference variable x is not affected by the m1() method.

Ref: http://www.javaworld.com/javaworld/javaqa/2000-05/03-qa-0526-pass.html[/details]