500 Servlet Exception

java.lang.NullPointerException
	at com.inc.conn.conn.executeQuery(conn.java:150)
	at com.inc.dbopt.mutiQuery.queryBiggestClass(mutiQuery.java:2694)
	at _manager._call_0yhxzarticle10__jsp._jspService(/manager/call_yhxzarticle10.jsp:38)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
	at com.caucho.jsp.Page.subservice(Page.java:506)
	at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
	at com.caucho.server.http.Invocation.service(Invocation.java:315)
	at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
	at com.caucho.server.http.QRequestDispatcher.include(QRequestDispatcher.java:364)
	at com.caucho.server.http.QRequestDispatcher.include(QRequestDispatcher.java:275)
	at com.caucho.jsp.QPageContext.include(QPageContext.java:550)
	at _index__jsp._jspService(_index__jsp.java:45)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
	at com.caucho.jsp.Page.subservice(Page.java:506)
	at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
	at com.caucho.server.http.Invocation.service(Invocation.java:315)
	at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
	at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:246)
	at com.caucho.server.http.HttpRequest.handleConnection(HttpRequest.java:163)
	at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
	at java.lang.Thread.run(Thread.java:536)