Obtain From Where a Class is Loaded
Java: How To
public class LoadingFromWhere
{
public static void main(String args[])
{
LoadingFromWhere s = new LoadingFromWhere();
s.doit();
}
public void doit()
{
System.out.println(this.getClass().getName() + " is loaded from " +
getClass().getProtectionDomain().getCodeSource().getLocation());
MyClass s = new MyClass();
}
}
class MyClass
{
MyClass()
{
System.out.println(this.getClass().getName() + " is loaded from " +
this.getClass().getProtectionDomain()
.getCodeSource().getLocation());
}
}
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The Output:
>java LoadingFromWhere
LoadingFromWhere is loaded from file:/C:/temp/
MyClass is loaded from file:/C:/temp/
Another Technique
public class FromWhere
{
public static void main(String args[])
{
Class theClass = java.lang.Object.class;
java.net.URL u = theClass.getResource("");
System.out.println("The Java RunTime used is located at : " + u);
theClass = FromWhere.class;
u = theClass.getResource("");
System.out.println("This class (FromWhere) is located at : " + u);
}
}
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The Output
> JAVA FromWhere
The Java RunTime used is located at : jar:file:/C:/DEV/java/jdk1.2.1/jre/lib/RT.JAR!/java/lang/
This class (FromWhere) is located at : null
How to Determine The Location of a Class Running From a JAR file
package com.gpp;
public class HelloClass
{
public static void main(String[] args)
{
new HelloClass().say();
}
public void say()
{
String className = this.getClass().getName().replace('.', '/');
String classJar = this.getClass().getResource(
"/" + className + ".class").toString();
if (classJar.startsWith("jar:"))
{
System.out.println("*** running from jar!");
}
System.out.println(classJar);
}
}
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The Output
jar cvfm Hello.jar manifest.mft com\rg
agnon\HelloClass.class
added manifest
adding: com/gpp/HelloClass.class (in=1059) (out=601) (deflated 43%)
java com.gpp.HelloClass
file:/C:/DEV/WORK/JAVA/com/gpp/HelloClass.class
java -jar Hello.jar
*** running from jar!
jar:file:/C:/DEV/WORK/JAVA/Hello.jar!/com/gpp/HelloClass.class
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