VelocityServlet : Error processing the template

java.lang.RuntimeException: IO Error: The Network Adapter could not establish the connection
java.lang.RuntimeException: IO Error: The Network Adapter could not establish the connection at com.threeis.webta.jdbc.DbAccessor.getConnection(DbAccessor.java:49) at com.threeis.webta.HelpServlet.handleRequest(HelpServlet.java:123) at org.apache.velocity.servlet.VelocityServlet.doRequest(VelocityServlet.java:331) at org.apache.velocity.servlet.VelocityServlet.doGet(VelocityServlet.java:292) at javax.servlet.http.HttpServlet.service(HttpServlet.java:489) at javax.servlet.http.HttpServlet.service(HttpServlet.java:583) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:679) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:617) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:934) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1690) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) at java.lang.Thread.run(Thread.java:750) Caused by: java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:743) at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:666) at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32) at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:566) at oracle.jdbc.pool.OracleDataSource.getPhysicalConnection(OracleDataSource.java:317) at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:241) at oracle.jdbc.pool.OracleConnectionPoolDataSource.getPhysicalConnection(OracleConnectionPoolDataSource.java:164) at oracle.jdbc.pool.OracleConnectionPoolDataSource.getPooledConnection(OracleConnectionPoolDataSource.java:102) at oracle.jdbc.pool.OracleImplicitConnectionCache.makeCacheConnection(OracleImplicitConnectionCache.java:1638) at oracle.jdbc.pool.OracleImplicitConnectionCache.makeOneConnection(OracleImplicitConnectionCache.java:528) at oracle.jdbc.pool.OracleImplicitConnectionCache.getCacheConnection(OracleImplicitConnectionCache.java:488) at oracle.jdbc.pool.OracleImplicitConnectionCache.getConnection(OracleImplicitConnectionCache.java:369) at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:443) at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:210) at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:184) at com.threeis.webta.jdbc.OracleConnectionManager.getConnection(OracleConnectionManager.java:216) at com.threeis.webta.jdbc.DbAccessor.getConnection(DbAccessor.java:35) ... 27 more Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:470) at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:510) at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:595) at oracle.net.ns.NSProtocol.connect(NSProtocol.java:230) at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1452) at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:496) ... 43 more Caused by: java.net.NoRouteToHostException: No route to host (Host unreachable) at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394) at java.net.Socket.connect(Socket.java:606) at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:161) at oracle.net.nt.ConnOption.connect(ConnOption.java:159) at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:428) ... 48 more