Compiling Java sources won’t produce executable which could be run independently. It produces binary code which is executed by Java. So in order to run Java program you need Java to be installed. Just to run a Java application JRE (Java Runtime Environment) should be enough. If you want to write Java application you will need JDK (Java Development Kit).

To install JRE on Linux with apt-get run

sudo apt-get install defaulf-jre

To install JDK on Linux with apt-get run

sudo apt-get install defaulf-jdk

To install JRE on Linux with yum run

sudo yum install java-1.8.0-openjdk

To install JDK on Linux with yum run

sudo yum install java-1.8.0-openjdk-devel

To install JRE/JDK on Windows go here. Please note that if you are installing JDK there is no need to install JRE; JDK comes with everything you need. Also I would recommend to add jdk/bin path to the system path (Control Panel -> System -> Advances system settings -> Environment Variables -> System variables -> Path)

To verify run in command prompt

java
javac

for both commands you should see Usage:… help.

Now let’s do a Hello World:

class HelloWorld
{
	public static void main(String args[])
	{
		System.out.println("Hello World from Java");
	}
}

save it as HelloWorld.java and to compile it run:

javac HelloWorld.java

to run:

java HelloWorld.class

Way too easy, isn’t it? In real life it’s a little bit more complicated than that.
First of all none has source files just lying around, everything is organized in what in Java called packages.
So let’s do it.
– create folder java1
– inside java1 one create folders src and classes
– and inside java1/src create folder ak
– create new file in java1/src/ak HelloWorld.java

package ak;

class HelloWorld
{
	public static void main(String args[])
	{
		System.out.println("Hello World from Java");
	}
}

please note that we added package name at the beginning of the file.

to compile it run:

javac -sourcepath src -d classes src/ak/HelloWorld.java

to run:

java -cp classes ak.HelloWorld

for the compiler we indicated where source file are and which folder to put class files
for the Java we indicated where classes are located and which is main class

And the last step. None deploys class files to a customer. Java application are usually distributed in jar files.
Let’s create a jar file:

jar cfv out/HelloWorld.jar -C classes .

to run

java -cp out/HelloWorld.jar ak.HelloWorld

for the Java we indicated where classes are located and which is main class

But we could simplify things by indicating which is the main class right inside jar file, we do it by creating what’s called manifest file:

echo Main-Class: ak.HelloWorld>manifest.mf

on Windows just create file manifest.mf

Manifest-version: 1.0
Main-Class: ak.HelloWorld

and now create new jar file

jar cfmv out/HelloWorld.jar manifest.mf -C classes .

and to run

java -jar out/HelloWorld.jar

notice that all we have to do is indicate jar file.