The difference between value passing and reference passing in Java

Because Java cancels the concept of pointers, developers often ignore the difference between objects and references in programming, such as Example 1

package xupt.edu.java.com;

public class TestRef
{
    public Obj aObj = new Obj();
    private int aInt = 0;

    public Obj getAObj()
    {
        return aObj;
    }

    public int getAInt()
    {
        return aInt;
    }

    public void changeObj(Obj inObj)
    {
        inObj.setStr("changed value");
    }

    public void changeInt(int inInt)
    {
        inInt = 1;
    }

    public static void main(String[] args)
    {
        TestRef oRef = new TestRef();
        System.out.println("*********引用类型*********");
        System.out.println("调用changeObj()前:" + oRef.getAObj());
        oRef.changeObj(oRef.getAObj());
        System.out.println("调用changeObj()后：" + oRef.getAObj());
        System.out.println("*********基本数据类型*********");
        System.out.println("调用changeInt()前:" + oRef.getAInt());
        oRef.changeInt(oRef.getAInt());
        System.out.println("调用changeInt()后：" + oRef.getAInt());
    }
}

class Obj
{
    public void setStr(String str)
    {
        this.str = str;
    }

    private String str = "default value";

    public String toString()
    {
        return str;
    }
}

The above two seemingly similar methods have different results. The main reason is that Java handles basic data types (such as int, char, double, etc.) by using value-by-value transfer (the input parameter is copied) Implementation, other types are executed by reference (passing a reference to an object).