What is System.out.println in java

What is System in java ?

                The System is a predefined class. Which is present in java. lang package. 

  • The System class is a final class and do not provide any public constructors. Because of this all of the members are methods contained in this class are static in nature. 
  • The System class also provides facilities like standard input, standard output, and error output Streams. it can't be instantiated.
What is System.out.println in java


   Methods present in System Class :-

  public final class java.lang.System {
      public static final java.io.InputStream in;
      public static final java.io.PrintStream out;
      public static final java.io.PrintStream err;
      public static void setIn(java.io.InputStream);
      public static void setOut(java.io.PrintStream);
      public static void setErr(java.io.PrintStream);
      public static java.io.Console console();
      public static java.nio.channels.Channel inheritedChannel() throws java.io.IOException;
      public static void setSecurityManager(java.lang.SecurityManager);
      public static java.lang.SecurityManager getSecurityManager();
      public static native long currentTimeMillis();
      public static native long nanoTime();
      public static native void arraycopy(java.lang.Object, int, java.lang.Object, int, int);
      public static native int identityHashCode(java.lang.Object);
      public static java.util.Properties getProperties();
      public static java.lang.String lineSeparator();
      public static void setProperties(java.util.Properties);
      public static java.lang.String getProperty(java.lang.String);
      public static java.lang.String getProperty(java.lang.String, java.lang.String);
      public static java.lang.String setProperty(java.lang.String, java.lang.String);
      public static java.lang.String clearProperty(java.lang.String);
      public static java.lang.String getenv(java.lang.String);
      public static java.util.Map<java.lang.String, java.lang.String> getenv();
      public static void exit(int);
      public static void gc();
      public static void runFinalization();
      public static void runFinalizersOnExit(boolean);
      public static void load(java.lang.String);
      public static void loadLibrary(java.lang.String);
      public static native java.lang.String mapLibraryName(java.lang.String);
      static {};
}


What is Out in java ?


                Out is a constant defined in System class but it is a reference of printStream class. and also Out is a Static field of System class.
        

What is print/println in java ?

                   print & println are non-static method defined in printStream Class .
  • As both the methods are object methods we call it outside class by the help of object.

Difference between print() and println() in java.

       Print() :-  It prints all the messages in a single line. There is no new line / break line                                    after printing the message.
       Println() :-  First it print the messages then it break that line and create a new line. It is                             used for creating a new line.

   What is System.out.println() in java ?

                In java System.out.println() is a Statement. Which is used for print the argument passed to it.

  Program for System.out.println() :-

        
public class program 
  {
public static void main(String args[])
{
System.out.println("I like java.");
}
  }
Output  :-
                             
What is System.out.println in java

Program - 2
class datas
{
public static final int data =100;
}
public class program1
{
public static void main(String args[])
{
System.out.printf("The value of data is  : "+datas.data);
}
}

     
What is System.out.println in java


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