    001    package org.junit.runners;
    002
    003    import org.junit.runners.model.InitializationError;
    004    import org.junit.runners.model.TestClass;
    005
    006    /**
    007     * Aliases the current default JUnit 4 class runner, for future-proofing. If
    008     * future versions of JUnit change the default Runner class, they will also
    009     * change the definition of this class. Developers wanting to explicitly tag a
    010     * class as a JUnit 4 class should use {@code @RunWith(JUnit4.class)}, not,
    011     * for example in JUnit 4.5, {@code @RunWith(BlockJUnit4ClassRunner.class)}.
    012     * This is the only way this class should be used--any extension that
    013     * depends on the implementation details of this class is likely to break
    014     * in future versions.
    015     *
    016     * @since 4.5
    017     */
    018    public final class JUnit4 extends BlockJUnit4ClassRunner {
    019        /**
    020         * Constructs a new instance of the default runner
    021         */
    022        public JUnit4(Class<?> klass) throws InitializationError {
    023            super(new TestClass(klass));
    024        }
    025    }