Essential Books

Instantiating and using a classloader

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This basic example shows how an application can instantiate a classloader and use it to dynamically load a class. 

URL[] urls = new URL[] {new URL("file:/home/me/extras.jar")};
Classloader loader = new URLClassLoader(urls);
Class<?> myObjectClass = loader.findClass("com.example.MyObject");

The classloader created in this example will have the default classloader as its parent, and will first try to find any class in the parent classloader before looking in “extra.jar”. If the requested class has already been loaded, the findClass call will return the reference to the previously loaded class.

The findClass call can fail in a variety of ways. The most common are:

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ClasssLoader:
* Classloaders
* Implementing a custom classLoader
* Loading an external .class file
* Instantiating and using a classloader
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0 Inheritance
1 Getting started with Java
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4 Collections
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84 The Classpath
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90 XML XPath Evaluation
91 Performance Tuning
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93 Common Pitfalls
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103 Just in Time JIT compiler
104 FTP File Transfer Protocol
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106 Modules
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118 Pitfalls - threads and concurrency
119 Splitting a string into fixed length parts
120 Pitfalls - nulls and NullPointerException
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124 java.util.Objects class
125 Java command: java and javaw
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152 Generating Java Code
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156 Multi-release JAR files
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159 Sockets
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176 Enum starting with a number
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180 StringBuffer
181 Choosing Collections
182 C++ Comparison
183 CompletableFuture
184 Contributors