#fixed code
                                @Override
    public void execute() throws MojoExecutionException, MojoFailureException {
        validateConfiguration();

        try {
            // set git flow configuration
            initGitFlowConfig();

            // check uncommitted changes
            checkUncommittedChanges();

            String tag = null;
            if (settings.isInteractiveMode()) {
                // get tags
                String tagsStr = gitFindTags();

                if (StringUtils.isBlank(tagsStr)) {
                    throw new MojoFailureException("There are no tags.");
                }

                try {
                    tag = prompter.prompt("Choose tag to start support branch",
                            Arrays.asList(tagsStr.split("\\r?\\n")));
                } catch (PrompterException e) {
                    throw new MojoFailureException("support-start", e);
                }
            } else if (StringUtils.isNotBlank(tagName)) {
                if (gitCheckTagExists(tagName)) {
                    tag = tagName;
                } else {
                    throw new MojoFailureException("The tag '" + tagName + "' doesn't exist.");
                }
            } else {
                getLog().info("The tagName is blank. Using the last tag.");
                tag = gitFindLastTag();
            }

            if (StringUtils.isBlank(tag)) {
                throw new MojoFailureException("Tag is blank.");
            }

            // git for-each-ref refs/heads/support/...
            final boolean supportBranchExists = gitCheckBranchExists(gitFlowConfig
                    .getSupportBranchPrefix() + tag);

            if (supportBranchExists) {
                throw new MojoFailureException(
                        "Support branch with that name already exists.");
            }

            // git checkout -b ... tag
            gitCreateAndCheckout(gitFlowConfig.getSupportBranchPrefix() + tag, tag);

            if (installProject) {
                // mvn clean install
                mvnCleanInstall();
            }

            if (pushRemote) {
                gitPush(gitFlowConfig.getSupportBranchPrefix() + tag, false);
            }
        } catch (CommandLineException e) {
            throw new MojoFailureException("support-start", e);
        }
    }
#vulnerable code 
                                @Override
    public void execute() throws MojoExecutionException, MojoFailureException {
        validateConfiguration();

        try {
            // set git flow configuration
            initGitFlowConfig();

            // check uncommitted changes
            checkUncommittedChanges();

            // get tags
            String tagsStr = gitFindTags();

            if (StringUtils.isBlank(tagsStr)) {
                throw new MojoFailureException("There are no tags.");
            }

            String tagName = null;
            try {
                tagName = prompter.prompt("Choose tag to start support branch",
                        Arrays.asList(tagsStr.split("\\r?\\n")));
            } catch (PrompterException e) {
                throw new MojoFailureException("support-start", e);
            }

            // git for-each-ref refs/heads/support/...
            final boolean supportBranchExists = gitCheckBranchExists(gitFlowConfig
                    .getSupportBranchPrefix() + tagName);

            if (supportBranchExists) {
                throw new MojoFailureException(
                        "Support branch with that name already exists.");
            }

            // git checkout -b ... tag
            gitCreateAndCheckout(gitFlowConfig.getSupportBranchPrefix()
                    + tagName, tagName);

            if (installProject) {
                // mvn clean install
                mvnCleanInstall();
            }

            if (pushRemote) {
                gitPush(gitFlowConfig.getSupportBranchPrefix() + tagName, false);
            }
        } catch (CommandLineException e) {
            throw new MojoFailureException("support-start", e);
        }
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE