#vulnerable code 
                                @BeforeClass
    public static void beforeClass() throws Exception {
        URL sqlProperties = Thread.currentThread().getContextClassLoader().getResource("sqlg.properties");
        configuration = new PropertiesConfiguration(sqlProperties);
        if (!configuration.containsKey("jdbc.url")) {
            throw new IllegalArgumentException(String.format("SqlGraph configuration requires that the %s be set", "jdbc.url"));
        }

        String url = configuration.getString("jdbc.url");
        //obtain the connection that we will later supply from JNDI
        SqlgPlugin p = findSqlgPlugin(url);
        Assert.assertNotNull(p);
        ds = new C3p0DataSourceFactory().setup(p.getDriverFor(url), configuration).getDatasource();
        //change the connection url to be a JNDI one
        configuration.setProperty("jdbc.url", "jndi:testConnection");

        //set up the initial context
        NamingManager.setInitialContextFactoryBuilder(environment -> {
            InitialContextFactory mockFactory = mock(InitialContextFactory.class);
            Context mockContext = mock(Context.class);
            when(mockFactory.getInitialContext(any())).thenReturn(mockContext);

            when(mockContext.lookup("testConnection")).thenReturn(ds);

            return mockFactory;
        });
    } 
                            #location 13 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @BeforeClass
    public static void beforeClass() throws Exception {
        URL sqlProperties = Thread.currentThread().getContextClassLoader().getResource("sqlg.properties");
        configuration = new PropertiesConfiguration(sqlProperties);
        if (!configuration.containsKey("jdbc.url")) {
            throw new IllegalArgumentException(String.format("SqlGraph configuration requires that the %s be set", "jdbc.url"));
        }

        ds = C3P0DataSource.create(configuration).getDatasource();

        //change the connection url to be a JNDI one
        configuration.setProperty("jdbc.url", "jndi:testConnection");

        //set up the initial context
        NamingManager.setInitialContextFactoryBuilder(environment -> {
            InitialContextFactory mockFactory = mock(InitialContextFactory.class);
            Context mockContext = mock(Context.class);
            when(mockFactory.getInitialContext(any())).thenReturn(mockContext);

            when(mockContext.lookup("testConnection")).thenReturn(ds);

            return mockFactory;
        });
    }