String s = "abc";
String repeated = new String(new char[3]).replace("\0", s);

result in repeated containing:

abcabcabc

This is sort-of a low-level predecessor to printing repeats using C# LINQ.

Compared to C#, Java does not allow to switch on string. However, this can still be done by wrapping the strings in an enum:

public class Switch {
  public static enum Days {
    Monday, 
    Tuesday, 
    Wednesday, 
    Thursday, 
    Friday,
    Unknown
 
  };
  public static void main(String [] args) {
    Days Day = Day.Monday;
    switch (Day) {
      case Monday:
      case Tuesday:
      case Wednesday:
      case Thursday:
      case Friday:
        System.out.println("Weekdays");
        break;
      default:
        System.out.println("Unknown day");
        break;
    }
  }
}

import java.io.*;
import java.net.*;
import java.util.*;
import static java.lang.System.out;
 
public class ListAddrs {
    public static void main(String args[]) throws SocketException {
        InetAddress localhost = InetAddress.getLocalHost();
        InetAddress[] allMyIps = InetAddress.getAllByName(localhost.getCanonicalHostName());
        for (int i = 0; i < allMyIps.length; i++)
            out.printf("InetAddress: %s\n", allMyIps[i]);
    }
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2016 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
public class Fibonacci {
    public static void main(String[] args) {
        int f0 = 0;
        int f1 = 1;
 
        int i = 0;
        while(i < 10) {
            int s = f0;
            f0 = f1;
            f1 = s + f1;
 
            System.out.println(s);
 
            i = i + 1;
        }
    }
}

The heap size can be specified by Xmx and he stack size by Xms whilst units can be used to express megabytes or gigabytes.

-Xmx512m -Xms512m