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    <p>A class at runtime is identified by both its fully qualified name and its ClassLoader.</p> <p>For example, when you test two <code>Class&lt;T&gt;</code> objects for equality, if they have the same canonical name but were loaded from different ClassLoaders, they won't be equal.</p> <p>For two classes to belong to the same package (and in turn being able to access package-private methods), they need to be loaded from the same ClassLoader too, which is not the case here. In fact <code>Test1</code> is loaded by the system classloader, while the Formula is loaded by the URLClassLoader created inside <code>loadClass()</code>. </p> <p>If you specify a parent loader for your URLClassLoader in order to make it load <code>Test1</code>, still two different loaders are used (you can check it by asserting loaders equality).</p> <p>I don't think you can make the <code>Formula</code> class loaded by the same <code>Test1</code> ClassLoader (you'd have to use a well-known path and put it on the CLASSPATH), but I found a way to do the opposite: loading another instance of <code>Test1</code> in the ClassLoader used for loading the formula. This is the layout in pseudocode:</p> <pre><code>class Test1 { public static void main(String... args) { loadClass(formula); } static void loadClass(location) { ClassLoader loader = new ClassLoader(); Class formula = loader.load(location); Class test1 = loader.load(Test1); // ... Method compute = test1.getMethod("compute"); compute.invoke(test1, formula); } static void compute(formula) { print formula; } } </code></pre> <p>Here is the <a href="http://pastebin.com/eN5DyBrC" rel="noreferrer">pastebin</a>. A couple of notes: I specifed a <code>null</code> parent for the URLClassLoader to avoid the issue listed above, and I manipulated strings to achieve the purpose - but don't know how robust this approach can be in other deployment scenarios. Also, the URLCLassLoader I used only searches in two directories to find class definitions, not all the entries listed in the CLASSPATH</p>
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    1. COHow could I load my class in the main class loader (the class is not available at compile time so I need to "download" the class file)?
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    2. CO@assylias Don't know if you can in that program, unless the TMP_PATH is well-known and added to the CLASSPATH before the program starts. You may try the opposite, loading `Test1` in the new loader (beside the trivial solution of not using package-private members)
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    3. CO@assylias It may be enough if you include a certain directory (e.g. C:/temp/) on your classpath, the classloader will read the class just then when you try to load it. At least UrlClassLoader does this. Just make sure that you save in a subdirectory according to the package structure (javaapplication4).
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