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26 lines
1.5 KiB
Markdown
26 lines
1.5 KiB
Markdown
[//]: # (title: Class Loaders)
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<!-- Copyright 2000-2022 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file. -->
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A separate class loader is used to load the classes of each plugin.
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This allows each plugin to use a different library version, even if the same library is used by the IDE itself or by another plugin.
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By default, the main IDE class loader loads classes that are not found in the plugin class loader.
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However, in the <path>plugin.xml</path> file, you may use the `<depends>` element to specify that a [plugin depends](plugin_dependencies.md) on one or more other plugins.
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In this case, the class loaders of those plugins will be used for classes not found in the current plugin.
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This allows a plugin to reference classes from other plugins.
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### Using ServiceLoader
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Some libraries use [`ServiceLoader`](https://docs.oracle.com/javase/8/docs/api/index.html?java/util/ServiceLoader.html) to detect and load implementations.
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For this to work in a plugin, the context class loader must be set to the plugin's classloader and restored afterwards with original one around initialization code:
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```java
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ClassLoader current = Thread.currentThread().getContextClassLoader();
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try {
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Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
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// code working with ServiceLoader here
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} finally {
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Thread.currentThread().setContextClassLoader(current);
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}
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```
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