Check if package exists at runtime

[Bruce Lee]

Is there anyway to check if a package exists at runtime? Class is simple -

try{
Class.forName("java.class1.Class12");
}catch(Exception e){}

but can you do this for a whole package?

 

[Damian Brunold]

Is there anyway to check if a package exists at runtime? Class is simple -

try{
Class.forName("java.class1.Class12");
}catch(Exception e){}

but can you do this for a whole package?

Package.getPackages() gets all packages known to the callers
ClassLoader. At least this is what the documentation says...

 

[Robert Klemme]

Package.getPackages() gets all packages known to the callers
ClassLoader. At least this is what the documentation says...

public static boolean packageExists(String name) {
return Package.getPackage(name)!=null;
}

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Package.html#getPackage(java.lang.String)

robert

 

[Stefan Schulz]

You can, if the package is sealed, just check if all classes can be
retrieved by Class.forName(). Otherwise, the notion of "whole package"
makes no sense, since there may be any number of classes also living in
that package you have never heared about.

 

[Chris Smith]

public static boolean packageExists(String name) {
return Package.getPackage(name)!=null;
}

Note that this will return true ONLY when a class from the package has
already been loaded. It does not somehow check if anything from the
package might be available in the future. That is the JVM's definition
of whether the package exists (it doesn't exist until it's first used),
but it's probably not the definition the OP wanted.

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