{@link org.netbeans.spi.java.classpath.support.ClassPathSupport} provides various ways to create {@link org.netbeans.api.java.classpath.ClassPath} objects beyond what the plain SPI provides.
{@link org.netbeans.spi.java.classpath.support.PathResourceBase} and {@link org.netbeans.spi.java.classpath.support.CompositePathResourceBase} can be used to define parts of a classpath in a controlled way.