#vulnerable code 
                                public static void main(String[] args) throws Exception {

        CommandLineParams commandLineParams = new CommandLineParams();

        JCommander jCommander = new JCommander(commandLineParams, args);

        if (commandLineParams.help) {
            jCommander.usage();
            System.exit(1);
        }
        
        // default to src/main/webapp
        if (commandLineParams.paths.size() == 0) {
             commandLineParams.paths.add("src/main/webapp");
        }

        final Tomcat tomcat = new Tomcat();

        // set directory for temp files
        tomcat.setBaseDir(resolveTomcatBaseDir(commandLineParams.port));

        // initialize the connector
        Connector nioConnector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
        nioConnector.setPort(commandLineParams.port);

        tomcat.setConnector(nioConnector);
        tomcat.getService().addConnector(tomcat.getConnector());

        tomcat.setPort(commandLineParams.port);
        
        if (commandLineParams.paths.size() > 1) {
            System.out.println("FYI... Since you specified more than one path, the context paths will be automatically set to the name of the path without the extension. A path that resolves to a context path of \"/ROOT\" will be replaced with \"/\"");
            
            if(commandLineParams.contextPath != null) {
                System.out.println("WARNING: context-path is ignored when more than one path or war file is specified");
            }
            if(commandLineParams.contextXml != null) {
                System.out.println("WARNING: context-xml is ignored when more than one path or war file is specified");
            }
        }

        Context ctx = null;
        
        for (String path : commandLineParams.paths) {
            File war = new File(path);
            
            if (!war.exists()) {
                System.err.println("The specified path \"" + path + "\" does not exist.");
                jCommander.usage();
                System.exit(1);
            }
            
            String ctxName = "";

            // Use the commandline context-path (or default) if there is only one war
            if (commandLineParams.paths.size() == 1) {
                // warn if the contextPath doesn't start with a '/'. This causes issues serving content at the context root.
                if (commandLineParams.contextPath.length() > 0 && !commandLineParams.contextPath.startsWith("/")) {
                    System.out.println("WARNING: You entered a path: [" + commandLineParams.contextPath + "]. Your path should start with a '/'. Tomcat will update this for you, but you may still experience issues.");
                }
                
                ctxName = commandLineParams.contextPath;
                
            }
            else {
                ctxName = "/" + FilenameUtils.removeExtension(war.getName());

                if (ctxName.equals("/ROOT") || (commandLineParams.paths.size() == 1)) {
                    ctxName = "/";
                }
            }
                
            System.out.println("Adding Context " + ctxName + " for " + war.getPath());
            //Context ctx = tomcat.addWebapp(ctxName, war.getAbsolutePath());
            
            
            ctx = tomcat.addWebapp(ctxName, war.getAbsolutePath());
        }
          
        if(!commandLineParams.shutdownOverride) {          
            final String ctxName = ctx.getName();
            // allow Tomcat to shutdown if a context failure is detected
            ctx.addLifecycleListener(new LifecycleListener() {
                public void lifecycleEvent(LifecycleEvent event) {
                    if (event.getLifecycle().getState() == LifecycleState.FAILED) {
                        Server server = tomcat.getServer();
                        if (server instanceof StandardServer) {
                            System.err.println("SEVERE: Context [" + ctxName + "] failed in [" + event.getLifecycle().getClass().getName() + "] lifecycle. Allowing Tomcat to shutdown.");
                            ((StandardServer) server).stopAwait();
                        }
                    }
                }
            });
        }
        
        
        
        // set the context xml location if there is only one war
        if(commandLineParams.contextXml != null && commandLineParams.paths.size() == 1) {
            System.out.println("Using context config: " + commandLineParams.contextXml);
            ctx.setConfigFile(new File(commandLineParams.contextXml).toURI().toURL());
        }

        // set the session manager
        if (commandLineParams.sessionStore != null) {
            SessionStore.getInstance(commandLineParams.sessionStore).configureSessionStore(commandLineParams, ctx);
        }

        //set the session timeout
        if(commandLineParams.sessionTimeout != null) {
            ctx.setSessionTimeout(commandLineParams.sessionTimeout);
        }
        
        commandLineParams = null;

        //start the server
        tomcat.start();
        tomcat.getServer().await();
    } 
                            #location 81 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public static void main(String[] args) throws Exception {

        CommandLineParams commandLineParams = new CommandLineParams();

        JCommander jCommander = new JCommander(commandLineParams, args);

        if (commandLineParams.help) {
            jCommander.usage();
            System.exit(1);
        }
        
        // default to src/main/webapp
        if (commandLineParams.paths.size() == 0) {
             commandLineParams.paths.add("src/main/webapp");
        }

        final Tomcat tomcat = new Tomcat();

        // set directory for temp files
        tomcat.setBaseDir(resolveTomcatBaseDir(commandLineParams.port));

        // initialize the connector
        Connector nioConnector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
        nioConnector.setPort(commandLineParams.port);

        tomcat.setConnector(nioConnector);
        tomcat.getService().addConnector(tomcat.getConnector());

        tomcat.setPort(commandLineParams.port);
        
        if (commandLineParams.paths.size() > 1) {
            System.out.println("WARNING: multiple paths are specified, but no longer supported. First path will be used.");
        }
        
        // Get the first path
        String path = commandLineParams.paths.get(0);

        Context ctx = null;
        
        File war = new File(path);
        
        if (!war.exists()) {
            System.err.println("The specified path \"" + path + "\" does not exist.");
            jCommander.usage();
            System.exit(1);
        }
        
        // Use the commandline context-path (or default)
        // warn if the contextPath doesn't start with a '/'. This causes issues serving content at the context root.
        if (commandLineParams.contextPath.length() > 0 && !commandLineParams.contextPath.startsWith("/")) {
            System.out.println("WARNING: You entered a path: [" + commandLineParams.contextPath + "]. Your path should start with a '/'. Tomcat will update this for you, but you may still experience issues.");
        }
        
        final String ctxName = commandLineParams.contextPath;
            
        System.out.println("Adding Context " + ctxName + " for " + war.getPath());
        
        ctx = tomcat.addWebapp(ctxName, war.getAbsolutePath());
          
        if(!commandLineParams.shutdownOverride) {          
            // allow Tomcat to shutdown if a context failure is detected
            ctx.addLifecycleListener(new LifecycleListener() {
                public void lifecycleEvent(LifecycleEvent event) {
                    if (event.getLifecycle().getState() == LifecycleState.FAILED) {
                        Server server = tomcat.getServer();
                        if (server instanceof StandardServer) {
                            System.err.println("SEVERE: Context [" + ctxName + "] failed in [" + event.getLifecycle().getClass().getName() + "] lifecycle. Allowing Tomcat to shutdown.");
                            ((StandardServer) server).stopAwait();
                        }
                    }
                }
            });
        }
        
        
        
        // set the context xml location if there is only one war
        if(commandLineParams.contextXml != null) {
            System.out.println("Using context config: " + commandLineParams.contextXml);
            ctx.setConfigFile(new File(commandLineParams.contextXml).toURI().toURL());
        }

        // set the session manager
        if (commandLineParams.sessionStore != null) {
            SessionStore.getInstance(commandLineParams.sessionStore).configureSessionStore(commandLineParams, ctx);
        }

        //set the session timeout
        if(commandLineParams.sessionTimeout != null) {
            ctx.setSessionTimeout(commandLineParams.sessionTimeout);
        }
        
        commandLineParams = null;

        //start the server
        tomcat.start();
        tomcat.getServer().await();
    }