How to use java -D in command prompt to pass something to all applications in my JVM?

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Java

class ExtensionClassLoader
{
	public static void main(String[] args)
	{
		String i=null;
		System.out.println("hello");
		i=System.getProperty(i);
	}
}

What I have tried:

Actually, I am trying to know about extension classloader. I am getting Nullpointer exception when i type (java -Di=10 ExtensionClassLoader) in command prompt.
Any information about this classloader or link to where can I find information will be highly appreciated.

Posted 22-Nov-16 15:49pm

Subham619

Updated 22-Nov-16 21:59pm

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Richard MacCutchan · Answer 1 · 2016-11-22T21:31:00

Solution 1

Java

String i=null;
System.out.println("hello");
i=System.getProperty(i);

What information do you think getProperty will return when you send it a value of null?
You need to pass the actual name of the property you wish to retrieve.

Posted 22-Nov-16 21:31pm

Richard MacCutchan