JvmOptions opts = createOpts()
        when:
        opts.defaultCharacterEncoding = "ISO-8859-1"
        then:
        opts.allJvmArgs.contains("-Dfile.encoding=ISO-8859-1");
    }

    def "uses system default file encoding when null is used"() {
        JvmOptions opts = createOpts()
        when:
        opts.defaultCharacterEncoding = null
        then:

        return immutableSystemProperties.get(FILE_ENCODING_KEY).toString();
    }

    public void setDefaultCharacterEncoding(String defaultCharacterEncoding) {
        immutableSystemProperties.put(FILE_ENCODING_KEY, GUtil.isTrue(defaultCharacterEncoding) ? defaultCharacterEncoding : Charset.defaultCharset().name());
    }

    public boolean getEnableAssertions() {
        return assertionsEnabled;
    }

        return javaOptions.getDefaultCharacterEncoding();
    }

    @Override
    public void setDefaultCharacterEncoding(String defaultCharacterEncoding) {
        javaOptions.setDefaultCharacterEncoding(defaultCharacterEncoding);
    }

    @Override
    public String getMaxHeapSize() {
        return javaOptions.getMaxHeapSize();
    }

    @Override

    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setDefaultCharacterEncoding(String defaultCharacterEncoding) {
        javaExecSpec.setDefaultCharacterEncoding(defaultCharacterEncoding);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getMaxHeapSize() {
        return javaExecSpec.getMaxHeapSize();
    }

        public void setEnvironment(Map<String, ?> environmentVariables) {
            throw new UnsupportedOperationException();
        }

        @Override
        public void setDefaultCharacterEncoding(String defaultCharacterEncoding) {
            throw new UnsupportedOperationException();
        }

        @Override
        public ProcessForkOptions environment(Map<String, ?> environmentVariables) {

    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setDefaultCharacterEncoding(String defaultCharacterEncoding) {
        forkOptions.setDefaultCharacterEncoding(defaultCharacterEncoding);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setMinHeapSize(String heapSize) {
        forkOptions.setMinHeapSize(heapSize);

     * Sets the default character encoding to use.
     *
     * Only makes sense for forking executers.
     *
     * @return this executer
     */
    GradleExecuter withDefaultCharacterEncoding(String defaultCharacterEncoding);

    /**
     * Sets the default locale to use.
     *
     * Only makes sense for forking executers.
     *
     * @return this executer
     */