Accessing Windows system variables in Java 1.4

Question

What is the best/foolproof way to get the values of environment variables in Windows when using J2SE 1.4 ?

Answer 1

You can use getEnv() to get environment variables:

String variable = System.getenv("WINDIR");  
System.out.println(variable);  

I believe the getEnv() function was deprecated at some point but then "undeprecated" later in java 1.5

ETA:

I see the question now refers specifically to java 1.4, so this wouldn't work for you (or at least you might end up with a deprecation warning). I'll leave the answer here though in case someone else stumbles across this question and is using a later version.

Answer 2

There's a switch to the JVM for this. From here:

Start the JVM with the "-D" switch to pass properties to the application and read them with the System.getProperty() method.

SET myvar=Hello world
SET myothervar=nothing
java -Dmyvar="%myvar%" -Dmyothervar="%myothervar%" myClass

then in myClass

String myvar = System.getProperty("myvar");
String myothervar = System.getProperty("myothervar");