A question about java.policy.

[dmjpro]

I want to permit the java application only to read any local file but i don't want any application to update a local file.
Is this related to java.policy?
Please suggest ....!

[r035198x]

I want to permit the java application only to read any local file but i don't want any application to update a local file.
Is this related to java.policy?
Please suggest ....!

No.
You can only control only what your Java program can read using policy files.

[dmjpro]

No.
You can only control only what your Java program can read using policy files.

If I change something odd in java.policy then what happens?

[r035198x]

If I change something odd in java.policy then what happens?

Google knows

[dmjpro]

Google knows

No no don't misunderstand me .... I want to discuss this over here instead of looking for Google.
What I did with this file that is, i changed a line permission java.security.F ilePermission within grant block for applet to do have acces to it's local file system.
That's why i asking about, if i want to change permission settings in java application which runs from the local except Applet code what i need to do.
Please have a discussion over here ..this is my earnest request to all of you experts .... :-)

[dmjpro]

No no don't misunderstand me .... I want to discuss this over here instead of looking for Google.
What I did with this file that is, i changed a line permission java.security.F ilePermission within grant block for applet to do have acces to it's local file system.
That's why i asking about, if i want to change permission settings in java application which runs from the local except Applet code what i need to do.
Please have a discussion over here ..this is my earnest request to all of you experts .... :-)

Sorry r035198x ... I went for details and now the picture is cleared to me. :-)

[r035198x]

Sorry r035198x ... I went for details and now the picture is cleared to me. :-)

Care to share what you found out?

[dmjpro]

Care to share what you found out?

What you told that's right.
The java.policy can't be changed just you can edit it through Program.
A code snippet is given below ..
[code=java]
System.setSecur ityManager(new SecurityManager (){
@Override
public void checkWrite(Stri ng file){
throw new SecurityExcepti on("File write not allowed..!!!");
}
});

FileWriter file = new FileWriter("d:/test.txt");
file.write("My name is Debasis Jana");
file.close();
[/code]
Here i am getting the security exception.
Now after main thread terminates the default permission set.

Now tell me r035198x, how java.policy works ..could you tell me in details? :-)

[dmjpro]

What you told that's right.
The java.policy can't be changed just you can edit it through Program.
A code snippet is given below ..
[code=java]
System.setSecur ityManager(new SecurityManager (){
@Override
public void checkWrite(Stri ng file){
throw new SecurityExcepti on("File write not allowed..!!!");
}
});

FileWriter file = new FileWriter("d:/test.txt");
file.write("My name is Debasis Jana");
file.close();
[/code]
Here i am getting the security exception.
Now after main thread terminates the default permission set.

Now tell me r035198x, how java.policy works ..could you tell me in details? :-)

I come back again here.
Actually still it's not clear how java.policy works?
When it's read up..Please tell me in brief. :-)

[r035198x]

I come back again here.
Actually still it's not clear how java.policy works?
When it's read up..Please tell me in brief. :-)

Which part is not clear? Did you read these links?
Link 1
Link 2

[dmjpro]

Which part is not clear? Did you read these links?
Link 1
Link 2

There is a long story ..lolz!
Ok let me read then I ll ask if something remains misunderstood.

[dmjpro]

There is a long story ..lolz!
Ok let me read then I ll ask if something remains misunderstood.

Ok ..let's start with something.
When i am setting the SecurityManager like....
[code=java]
System.setSecur ityManager(new SecurityManager (){
//my code goes here
});
[/code]
It means i am simply overriding the default implementation of java policy.
Once I start this then how long it alives unless i set it to default SecurityManager .
Please explain!

[dmjpro]

Ok ..let's start with something.
When i am setting the SecurityManager like....
[code=java]
System.setSecur ityManager(new SecurityManager (){
//my code goes here
});
[/code]
It means i am simply overriding the default implementation of java policy.
Once I start this then how long it alives unless i set it to default SecurityManager .
Please explain!

Where are you r035198x?
Please Help!

[r035198x]

Use this method instead as explained in one of those links

  java -Djava.security.manager -Djava.security.policy=yourPolicy YourApp

It's much safer that way.

[JosAH]

Where are you r035198x?
Please Help!

Look what happens if you attempt to constuct a SecurityManager :

If there is a security manager already installed, this method first calls the security manager's checkPermission method with the RuntimePermissi on("createSecur ityManager") permission to ensure the calling thread has permission to create a new security manager. This may result in throwing a SecurityExcepti on.

kind regards,

Jos

ps. and please don't yell for attention.