Set an environment Variable in Java.

[dmjpro]

There is an API to get the environment variable, "System.getEnv".
But there is no setEnv method ?
Was there any problem to implement that?
Please explain ???

Debasis Jana.

[JosAH]

There is an API to get the environment variable, "System.getEnv".
But there is no setEnv method ?
Was there any problem to implement that?
Please explain ???

Debasis Jana.

You don't need it; if you want a changeable environment you can build your own:

public class MyEnvironment extends HashMap<String, String> {
 
   // singleton
   private MyEnvironment env;
   public synchronized MyEnvironment getInstance() {
      if (env == null)
         env= new MyEnvironment(System.getEnv());
      return env;
   }
 
   private MyEnvironment(Map<String, String> copy) {
      super(copy);
   }
}
 

kind regards,

Jos

[dmjpro]

You don't need it; if you want a changeable environment you can build your own:

public class MyEnvironment extends HashMap<String, String> {
 
   // singleton
   private MyEnvironment env;
   public synchronized MyEnvironment getInstance() {
      if (env == null)
         env= new MyEnvironment(System.getEnv());
      return env;
   }
 
   private MyEnvironment(Map<String, String> copy) {
      super(copy);
   }
}
 

kind regards,

Jos

Thanks for your reply ....!
But how could I make it persistent ???
Should I use Serialization?

Anyway one more thing ..why SUN failed to design System.setEnv?
I need this explain ..please!

Debasis Jana

[JosAH]

Thanks for your reply ....!
But how could I make it persistent ???
Should I use Serialization?

Anyway one more thing ..why SUN failed to design System.setEnv?
I need this explain ..please!

Debasis Jana

Sun didn't fail in designing that method because, as I wrote before, you don't
need it; have a look at the Runtime.exec( ... ) methods: you can pass it
an environment yourself so you don't have to pass it your own environment. It
simply isn't needed to alter your own environment.

kind regards,

Jos

[dmjpro]

Sun didn't fail in designing that method because, as I wrote before, you don't
need it; have a look at the Runtime.exec( ... ) methods: you can pass it
an environment yourself so you don't have to pass it your own environment. It
simply isn't needed to alter your own environment.

kind regards,

Jos

I came to know that ..but it is platform dependent ..
That's why I asked.

Anyway thanks for your help.
But how could I make that persistent ...because after JVM shuts down then how could I get my own Environment?

Debasis Jana

[JosAH]

I came to know that ..but it is platform dependent ..
That's why I asked.

Anyway thanks for your help.
But how could I make that persistent ...because after JVM shuts down then how could I get my own Environment?

Debasis Jana

That's not how environments work: when a process terminates its environment
is gone as well.

kind regards,

Jos

[dmjpro]

That's not how environments work: when a process terminates its environment
is gone as well.

kind regards,

Jos

Then how these work????
JAVA_HOME ..... something something ..... these set always ..
how??

Debasis Jana.

[JosAH]

Then how these work????
JAVA_HOME ..... something something ..... these set always ..
how??

Debasis Jana.

So you have forgotten that it's you who set that variable one day in the past?
It didn't end up in your environment automagically.

And if you're innocent some other process passed it on to its child process,
just like you did in your Runtime.exec() call.

kind regards,

Jos

[dmjpro]

So you have forgotten that it's you who set that variable one day in the past?
It didn't end up in your environment automagically.

And if you're innocent some other process passed it on to its child process,
just like you did in your Runtime.exec() call.

kind regards,

Jos

Yeah GOT man ..thanks a lot again!

Debasis Jana!

[jl880703]

Hi iam facing a similar problem but i just need to set the User when executing a Process and i dont need to save the enviroment could someone help me with this

[jkmyoung]

Do you mean windows user? Is this like "Run As Administrator?" Start your own thread for your own question.