1. What is Java? Java is a general-purpose programming language that is class-based, object-oriented and is very popular. It’s one of the most popular programming languages in the world. Hello World in Java: public class FileName { public static void main(String args[]) { System.out.println("Hello World!"); } } 2. How to install Java? Install Java through command prompt so that it can generate necessary log files to troubleshoot the issue. Go to java.com and click on the Free Java Download button. Click on the Save button and save Java software on the Desktop Verify that Java software is saved on the desktop. Open Windows Command Prompt window. Windows XP: Click Start -> Run -> Type: cmd Windows Vista and Windows 7: Click Start -> Type: cmd in the Start Search field. cd <Java download directory> (for example Downloads or Desktop etc.) IRun the installer and follow onscreen instructions. 3. How to reverse a string in Java? "String str = "&qu