#vulnerable code 
                                public void updateSecureConnection(
            final OperatedClientConnection conn,
            final HttpHost target,
            final HttpContext context,
            final HttpParams params) throws IOException {
        if (conn == null) {
            throw new IllegalArgumentException("Connection may not be null");
        }
        if (target == null) {
            throw new IllegalArgumentException("Target host may not be null");
        }
        if (params == null) {
            throw new IllegalArgumentException("Parameters may not be null");
        }
        if (!conn.isOpen()) {
            throw new IllegalStateException("Connection must be open");
        }

        final Scheme schm = schemeRegistry.getScheme(target.getSchemeName());
        if (!(schm.getSchemeSocketFactory() instanceof LayeredSchemeSocketFactory)) {
            throw new IllegalArgumentException
                ("Target scheme (" + schm.getName() +
                 ") must have layered socket factory.");
        }

        LayeredSchemeSocketFactory lsf = (LayeredSchemeSocketFactory) schm.getSchemeSocketFactory();
        Socket sock;
        try {
            sock = lsf.createLayeredSocket(
                    conn.getSocket(), target.getHostName(), target.getPort(), true);
        } catch (ConnectException ex) {
            throw new HttpHostConnectException(target, ex);
        }
        prepareSocket(sock, context, params);
        conn.update(sock, target, lsf.isSecure(sock), params);
    } 
                            #location 35 
                            #vulnerability type INTERFACE_NOT_THREAD_SAFE
#fixed code
                                public void updateSecureConnection(
            final OperatedClientConnection conn,
            final HttpHost target,
            final HttpContext context,
            final HttpParams params) throws IOException {
        if (conn == null) {
            throw new IllegalArgumentException("Connection may not be null");
        }
        if (target == null) {
            throw new IllegalArgumentException("Target host may not be null");
        }
        if (params == null) {
            throw new IllegalArgumentException("Parameters may not be null");
        }
        if (!conn.isOpen()) {
            throw new IllegalStateException("Connection must be open");
        }

        final Scheme schm = schemeRegistry.getScheme(target.getSchemeName());
        if (!(schm.getSchemeSocketFactory() instanceof SchemeLayeredSocketFactory)) {
            throw new IllegalArgumentException
                ("Target scheme (" + schm.getName() +
                 ") must have layered socket factory.");
        }

        SchemeLayeredSocketFactory lsf = (SchemeLayeredSocketFactory) schm.getSchemeSocketFactory();
        Socket sock;
        try {
            sock = lsf.createLayeredSocket(
                    conn.getSocket(), target.getHostName(), target.getPort(), params);
        } catch (ConnectException ex) {
            throw new HttpHostConnectException(target, ex);
        }
        prepareSocket(sock, context, params);
        conn.update(sock, target, lsf.isSecure(sock), params);
    }