- FAQ 94: What is a plug-in?
- FAQ 95: Do I use plugin or plug-in?
- FAQ 96: What is the plug-in manifest file (plugin.xml)?
- FAQ 97: How do I make my plug-in connect to other plug-ins?
- FAQ 98: What are extensions and extension points?
- FAQ 99: What is an extension point schema?
- FAQ 100: How do I find out more about a certain extension point?
- FAQ 101: When does a plug-in get started?
- FAQ 102: Where do plug-ins store their state?
- FAQ 103: How do I find out the install location of a plug-in?
- FAQ 104: What is the classpath of a plug-in?
- FAQ 105: How do I add a library to the classpath of a plug-in?
- FAQ 106: How can I share a JAR among various plug-ins?
- FAQ 107: How do I use the context class loader in Eclipse?
- FAQ 108: Why doesnt Eclipse play well with Xerces?
- FAQ 109: What is a plug-in fragment?
- FAQ 110: Can fragments be used to patch a plug-in?
- FAQ 111: What is a configuration?
- FAQ 112: How do I find out whether the Eclipse Platform is running?
- FAQ 113: Where does System.out and System.err output go?
- FAQ 114: How do I locate the owner plug-in from a given class?
- FAQ 115: How does OSGi and the new runtime affect me?
- FAQ 116: What is a dynamic plug-in?
- FAQ 117: How do I make my plug-in dynamic enabled?
- FAQ 118: How do I make my plug-in dynamic aware?
This chapter is from the book
This chapter is from the book
This chapter is from the book
FAQ 107: How do I use the context class loader in Eclipse?
In Java, each thread can optionally reference a context class loader. This loader can be set at any time by an application and is used for loading classes only when it is explicitly requested to do so. Many code libraries, in particular Java Database Connectivity (JDBC) and Xerces, use the context class loader in factory methods to allow clients of the library to specify what class loader to use. Although the context loader is not used by Eclipse itself, you may need to be aware of it when referencing third-party libraries from within Eclipse.
By default, the context loader is set to be the application class loader, which is not used in Eclipse. Because Eclipse has a separate class loader for each installed plug-in, a default class loader generally does not make sense as the context loader for a given thread. If you are calling third-party libraries that rely on the context loader, you will need to set it yourself. The following code snippet sets the context class loader before calling a library. Note that the code politely cleans up afterward by resetting the context loader to its original value:
Thread current = Thread.currentThread();
ClassLoader oldLoader = current.getContextClassLoader();
try {
current.setContextClassLoader(getClass().getClassLoader());
//call library code here
} finally {
current.setContextClassLoader(oldLoader);
}
Note
FAQ 104 What is the classpath of a plug-in?