Checking/getting JAVA_HOME Variable from Java

Question

Inside a Java program, how can I read the JAVA_HOME variable (to be sure it is set the correct way)? Similarly, how can I get the path of the bin folder? That is, the path usually set in Windows via:

path %path%;%JAVA_HOME%\bin

Note: I am using the OpenJDK build by Alexkasko.

Answer 1

Since both PATH and JAVA_HOME are environment variables, you should be able to read both of their values in a similar way:

String javaHome = System.getenv("JAVA_HOME");
String path = System.getenv("PATH");

Answer 2

Try

String javaHome = System.getProperty("java.home");

Answer 3

Use System.getenv() to read the value.

 System.getenv("JAVA_HOME");

Answer 4

You have to use System.getenv("JAVA_HOME");

Answer 5

On windows you could execute the set command from you application as you would do in your cmd and afterwards handle the output:

Process p;
p = Runtime.getRuntime().exec("set JAVA_HOME");

BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));

But as answered by the others

System.getenv("JAVA_HOME");

would be the nicer way.

However if anyone needs an alternative, see above. :D