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README.md

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 #j2js-compiler
 
 A Java Bytecode to JavaScript Cross-Compiler.
+
+##Installation
+
+1. You need to install this and the following projects
+
+* https://github.com/decatur/j2js-compiler
+* https://github.com/decatur/j2js-jre
+* https://github.com/decatur/j2js-agent
+
+2. Build all projects. An Eclipse project description is included.
+
+3. Optionally install https://github.com/decatur/j2js-demos
+
+##Usage
+
+    java -cp <RUNTIME_CLASSPATH> com.j2js.J2JSCompiler <basedir> <CROSS_COMPILE_CLASSPATH> <entryPointClassName> <targetLocation>
+
+###`<RUNTIME_CLASSPATH>`
+
+This is the standard Java classpath.
+The cross-compiler needs the project j2js-compiler, bcel and commons-io on its classpath. 
+
+###`<basedir>`
+
+All non-absolute paths are relative to the basedir.
+
+###`<entryPointClassName>`
+
+The name of the class to cross-compile. This class must have a method
+`public void main(java.lang.String[])`.
+
+The compiler cross-compiles the `main` method and all other methods which are called from the `main` method.
+
+###`<CROSS_COMPILE_CLASSPATH>`
+
+This classpath must contain all classes whose methods are referenced by the main method.
+In normal operation, this classpath consists of
+* the j2js-jre classes directory or jar
+* the j2js-agent classes directory or jar
+* the classes directory of your personal project
+
+###`<targetLocation>`
+All cross-compiled code is stored in the target location. It is one or more JavaScript file starting at
+`0.js`. Only this initial file must be included in your web page with
+`<script src='targetLocation/0.js'/>`.
+
+###Example
+
+Suppose the directory layout is
+
+    |- j2js-compiler
+    |- j2js-jre
+    |- j2js-agent
+    |- my-project
+         |- target
+             |- assemblies
+                 |- 0.js
+                 |- 1.js
+                 |- 2.js ...
+
+and you want to cross-compile class `org.mydomain.my-project.MyClass`. Then
+    
+    java -cp ../j2js-compiler/libs/commons-io-1.4.jar;^
+    ../j2js-compiler/libs/bcel-5.1.jar;^
+    ../j2js-compiler/target/classes ^
+    com.j2js.J2JSCompiler . ^
+    target/classes;../j2js-jre/target/classes;../j2js-agent/target/classes ^
+    org.mydomain.my-project.MyClass target/assemblies
+
+will create the assemblies.
+
+##Warning
+The project j2js-jre contains a hand-crafted version of the Java Runtime Environment. Do not substitute the path
+to this project by a path to `Java/jreX/lib/rt.jar`. 
+