String object with operation

[Claire Chan]

class StringObject{
   private String strVal;
   public StringObject(String str){ this.strVal= str; }
}
public class Tester{
    public static void main(String[] args) {
        StringObject so = new StringObject("World");
        StringBuilder sb = new StringBuilder("World");
        System.out.println("Hello, "+so);
        System.out.println("Hello, "+sb);
   }
}

Can anyone please explain to me why above code output is

Hello, StringObject@<hascode>
Hello, World

I understand StringBuilder value but not value from StringObject

Thanks

[Roel De Nijs]

Claire Chan wrote:I understand StringBuilder value but not value from StringObject

What did you expect as output for StringObject object?

[João Victor Gomes]

When you try to print and object, the toString() method is called, but your class StringObject doesn't override the toString() method, so it uses the one inherited from Object, which prints this pattern of the type of the object plus @ plus hash code, as you can see in the Java documentation.

If you override the method toString, you can have another result, like this:

class StringObject{
   private String strVal;

   public StringObject(String strVal) {
   		this.strVal= strVal;
   }

   public String toString() {
   		return strVal; //here you return the value that you want to represent your object
   }
}

public class Tester {
    public static void main(String[] args) {
        StringObject so = new StringObject("World");
        StringBuilder sb = new StringBuilder("World");

        System.out.println("Hello, " + so);
        System.out.println("Hello, " + sb);
   }
}