java - 方法中的Java 1D数组设置

我想知道类test1的两个数组testSet和testSet2
在方法problem（）中，testSet初始化为1，而testSet2初始化为0
在用testSet均衡testSet2之后，testSet2的长度与testSet相同，这很好
但
在方法problem1（）中，将testSet初始化为1，将testSet2初始化为0
并且在方法equalize（）中均衡后，使用testSet的testSet2的testSet2长度仍然为0。
为什么？

public class test1
{
    // C
    public test1(int _data)
    {
        data = _data;
    }

    // Field
    public int data;
}

// reference equalize method
public void equalize(test1[] a,test1[] b)
{
    a = b;
}

public test1[] testSet,testSet2; // arrays

// called from main method access
public void Problem()
{
    // initializing array
    testSet = new test1[1];
    testSet2 = new test1[0];

    testSet [0] = new test1 (11);
    testSet2 = testSet;

    // testSet2.length = 1 which is fine
}

// called from main method access
public void Problem1()
{
    testSet = new test1[1];
    testSet2 = new test1[0];

    testSet [0] = new test1 (11);
    equalize (testSet2,testSet);

    // want to know why this is happening ?
    // testSet2.length = 0
    // in problem() length = 1 but here is 0 why?
}

最佳答案

之所以testSet2 = 0的长度，是因为equalize（）方法仅在内部使用它们。 Methods（）仅代表参数使用参数。

如果要更改testSet2的长度。在上启动它

  public TestClass(int _data)
   {
        data = _data;
    testSet2 = new TestClass[0];
}

 and when you want to change it's length try this

 public void Problem1()
{
testSet = new TestClass[1];
testSet [0] = new TestClass (11);
 equalize (testSet);

System.out.println(testSet2.length);
System.out.println(testSet.length);



 }

  public void equalize(TestClass[] b)
{
testSet2 = b;
 }