How does System.out.println() method work?

What I see is that "out" is a static class variable in System class of type PrintStream. ( from the API )...

Since println() found in PrintStream class is not a static method, you need an object to call its method. ( You can not just say PrintStream.println("Hello World..")...

System class has a reference (PrintStream out) in its fields. But where is the object?

I will answer my own question:

Code:

---

package myPackage;

public class MyPrintStreamClass
{
        public void bark()
        {
                System.out.println("Bark!");
        }
}

---

Code:

---

package myPackage;

public class MySystemClass
{
        public static final MyPrintStreamClass outt = new MyPrintStreamClass();
}

---

Code:

---

package myPackage;

public class MyTestClass
{
        public static void main(String[] args)
        {
                MySystemClass.outt.bark();
        }
}

---

( This is for discussion and helping purposes. )


//

You can also do something like this:

Code:

---

PrintStream consoleOutputStream = new PrintStream(System.out);
                consoleOutputStream .println("Hello");

---

What you are doing here is:
Defining a variable pointing to a PrintStream object,
that is a copy of the object that is in System Class.

So the field out in System class, which is type of PrintStream is already pointing to an Object.

Quote:

---

Originally Posted by fatabass

You can also do something like this:

Code:

---

PrintStream consoleOutputStream = new PrintStream(System.out);
                consoleOutputStream .println("Hello");

---

What you are doing here is:
Defining a variable pointing to a PrintStream object,
that is a copy of the object that is in System Class.

---

It's not a copy.

It is a (pointless) wrapping of the existing PrintStream object from System inside of another PrintStream object.

So consoleOutputStream is referencing a PrintStream object, that we have created by saying new PrintStream().
and what we are passing into the PrintStream() constructor is: System.out
Which is a reference itself, that is pointing to an already existing PrintStream Object.

which means:

consoleOutput --> A PrintStreamObject(System.out --> Already Existing Object)

That's correct.

Thank you.