Bug 37197 Basepath for relative pathes in JAR-exporter
The basepath for the JAR-exporter is the eclipse-install-directory. I prefer it to be the root of the project (the description is saved in), so that relative pathes end inside the project. Now: <jardesc> <jar path="workspace/projectdir/jar.jar"/> Desired: <jardesc> <jar path="jar.jar"/> Reason: To make the jardesc-files portable for shared projects
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/jarpackager/JarPackageData.java
/**
	 * Creates and returns a JAR package data description writer
	 * for this JAR package data object.
	 * <p>
     * It is the client's responsibility to close this writer.
	 * </p>
	 * @param outputStream	the output stream to write to
	 * @return a JarWriter
	 */
	public IJarDescriptionWriter createJarDescriptionWriter(OutputStream outputStream) {
		return new JarPackageWriter(outputStream);
	}
	
	/**
	 * Creates and returns a JAR package data description reader
	 * for this JAR package data object.
	 * <p>
     * It is the client's responsibility to close this reader.
	 * </p>
	 * @param inputStream	the input stream to read from
	 * @return a JarWriter
	 */
	public IJarDescriptionReader createJarDescriptionReader(InputStream inputStream) {
		return new JarPackageReader(inputStream);
	}
	
	/**
	 * Tells whether this JAR package data can be used to generate
	 * a valid JAR.