Help myeclipse6.5 + tomcat

Began to learn jsp, wrote a jsp operation through Oracle's program ( in essence, according to the book examples copied ) , the code should be no problem . By tomcat deployment time , Myeclipse an error as follows:
Problems occurred when invoking code from plug-in: "org.eclipse.jface".
See the error log as follows:

Problems occurred when invoking code from plug-in: "org.eclipse.jface".

java.lang.NullPointerException
at com.genuitec.eclipse.ast.deploy.core.ui.dialog.DeploymentLabelProvider.getColumnText (Unknown Source)
at org.eclipse.jface.viewers.TableColumnViewerLabelProvider.update (TableColumnViewerLabelProvider.java: 70)
at org.eclipse.jface.viewers.ViewerColumn.refresh (ViewerColumn.java: 135)
at org.eclipse.jface.viewers.AbstractTableViewer.doUpdateItem (AbstractTableViewer.java: 386)
at org.eclipse.jface.viewers.StructuredViewer $ UpdateItemSafeRunnable.run (StructuredViewer.java: 466)
at org.eclipse.core.runtime.SafeRunner.run (SafeRunner.java: 37)
at org.eclipse.core.runtime.Platform.run (Platform.java: 857)
at org.eclipse.ui.internal.JFaceUtil $ 1.run (JFaceUtil.java: 46)
at org.eclipse.jface.util.SafeRunnable.run (SafeRunnable.java: 199)
at org.eclipse.jface.viewers.StructuredViewer.updateItem (StructuredViewer.java: 2026)
at org.eclipse.jface.viewers.AbstractTableViewer.createItem (AbstractTableViewer.java: 264)
at org.eclipse.jface.viewers.AbstractTableViewer.internalRefreshAll (AbstractTableViewer.java: 741)
at org.eclipse.jface.viewers.AbstractTableViewer.internalRefresh (AbstractTableViewer.java: 633)
at org.eclipse.jface.viewers.AbstractTableViewer.internalRefresh (AbstractTableViewer.java: 620)
at org.eclipse.jface.viewers.AbstractTableViewer $ 2.run (AbstractTableViewer.java: 576)
at org.eclipse.jface.viewers.StructuredViewer.preservingSelection (StructuredViewer.java: 1368)
at org.eclipse.jface.viewers.StructuredViewer.preservingSelection (StructuredViewer.java: 1330)
at org.eclipse.jface.viewers.CheckboxTableViewer.preservingSelection (CheckboxTableViewer.java: 295)
at org.eclipse.jface.viewers.AbstractTableViewer.inputChanged (AbstractTableViewer.java: 574)
at org.eclipse.jface.viewers.ContentViewer.setInput (ContentViewer.java: 251)
at org.eclipse.jface.viewers.StructuredViewer.setInput (StructuredViewer.java: 1606)
at com.genuitec.eclipse.ast.deploy.core.ui.dialog.DeploymentManagerDialog.updateDeploymentsViewerForProject (Unknown Source)
at com.genuitec.eclipse.ast.deploy.core.ui.dialog.DeploymentManagerDialog.handleProjectsComboBoxModified (Unknown Source)
at com.genuitec.eclipse.ast.deploy.core.ui.dialog.DeploymentManagerDialog $ 1.modifyText (Unknown Source)
at org.eclipse.swt.widgets.TypedListener.handleEvent (TypedListener.java: 166)
at org.eclipse.swt.widgets.EventTable.sendEvent (EventTable.java: 66)
at org.eclipse.swt.widgets.Widget.sendEvent (Widget.java: 938)
at org.eclipse.swt.widgets.Widget.sendEvent (Widget.java: 962)
at org.eclipse.swt.widgets.Widget.sendEvent (Widget.java: 943)
at org.eclipse.swt.widgets.Combo.wmCommandChild (Combo.java: 2327)
at org.eclipse.swt.widgets.Control.WM_COMMAND (Control.java: 3801)
at org.eclipse.swt.widgets.Control.windowProc (Control.java: 3675)
at org.eclipse.swt.widgets.Display.windowProc (Display.java: 4351)
at org.eclipse.swt.internal.win32.OS.CallWindowProcW (Native Method)
at org.eclipse.swt.internal.win32.OS.CallWindowProc (OS.java: 2179)
at org.eclipse.swt.widgets.Combo.callWindowProc (Combo.java: 282)
at org.eclipse.swt.widgets.Control.windowProc (Control.java: 3760)
at org.eclipse.swt.widgets.Combo.windowProc (Combo.java: 2045)
at org.eclipse.swt.widgets.Display.windowProc (Display.java: 4364)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW (Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage (OS.java: 2265)
at org.eclipse.swt.widgets.Display.readAndDispatch (Display.java: 3291)
at org.eclipse.jface.window.Window.runEventLoop (Window.java: 820)
at org.eclipse.jface.window.Window.open (Window.java: 796)
at com.genuitec.eclipse.ast.deploy.core.ui.action.DeploymentMgmtActionDelegate.runWithEvent (Unknown Source)
at org.eclipse.ui.internal.PluginAction.runWithEvent (PluginAction.java: 246)
at org.eclipse.ui.internal.WWinPluginAction.runWithEvent (WWinPluginAction.java: 229)
at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection (ActionContributionItem.java: 546)
at org.eclipse.jface.action.ActionContributionItem.access $ 2 (ActionContributionItem.java: 490)
at org.eclipse.jface.action.ActionContributionItem $ 6.handleEvent (ActionContributionItem.java: 443)
at org.eclipse.swt.widgets.EventTable.sendEvent (EventTable.java: 66)
at org.eclipse.swt.widgets.Widget.sendEvent (Widget.java: 938)
at org.eclipse.swt.widgets.Display.runDeferredEvents (Display.java: 3682)
at org.eclipse.swt.widgets.Display.readAndDispatch (Display.java: 3293)
at org.eclipse.ui.internal.Workbench.runEventLoop (Workbench.java: 2389)
at org.eclipse.ui.internal.Workbench.runUI (Workbench.java: 2353)
at org.eclipse.ui.internal.Workbench.access $ 4 (Workbench.java: 2219)
at org.eclipse.ui.internal.Workbench $ 4.run (Workbench.java: 466)
at org.eclipse.core.databinding.observable.Realm.runWithDefault (Realm.java: 289)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench (Workbench.java: 461)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench (PlatformUI.java: 149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start (IDEApplication.java: 106)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run (EclipseAppHandle.java: 169)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication (EclipseAppLauncher.java: 106)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start (EclipseAppLauncher.java: 76)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run (EclipseStarter.java: 363)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run (EclipseStarter.java: 176)
at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke (Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke (Unknown Source)
at java.lang.reflect.Method.invoke (Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework (Main.java: 508)
at org.eclipse.equinox.launcher.Main.basicRun (Main.java: 447)
at org.eclipse.equinox.launcher.Main.run (Main.java: 1173)
at org.eclipse.equinox.launcher.Main.main (Main.java: 1148)


White does not know how to solve this problem , please help ! Thank you first !

PS: a bit confused want to consult you about, how to write the program when it treats API , such as operation of the database used in the statement interface view API, the next one is a way to see it, or look at methods probably introduced , and then used the next time and then check the other way to do that ? The current study is to knock the books on the case, then your own debugger , seeking to share learning method !

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remember when just beginning to learn web often encounter this exception NullPointerException


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code should be no problem if the landlord look correct on your tomcat , tomcat general is the reason , I remember one time I was open tomcat default with, and then turn on again , also appeared this anomaly .
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have not selected the correct tomcat deployment ? not, then all deleted , again. . .
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your turn refers to the so-called services and Myeclipse start tomcat? Both are open !  

must turn off one , two open such a situation occurs .
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all deleted again ! Just learning when we must learn to coherent . Step by step, do not mess , or can not find where the problem lies
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er er, share !
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should be no problem , and I did not use myeclipse own tomcat, using tomcat6.0, jdk path of what is right in the browser, type localhost: 8080 is also the interface , there should be no issues now !
------ For reference only -------------------------------------- -

your turn refers to the so-called services and Myeclipse start tomcat? Both are open !
------ For reference only -------------------------------------- -

code is not the problem, his novice , is a shining example of knocking , the pro ! It is debugging problems !
------ For reference only -------------------------------------- -

your turn refers to the so-called services and Myeclipse start tomcat? Both are open !    

  

  
  
must turn off one , two open such a situation occurs .  

is the problem , has good debugging , thank you !
------ For reference only -------------------------------------- -
Thank you for your answer , the problem has been resolved, is open in Myeclipse server , then do not specifically in the Window's service and then open the tomcat service , thank you for your answer carefully !
Another point is that although it kept saying the code is not a problem , but in the normal operation of the program or when there is some small problem, knock on the wrong spelling of their own , After more careful job ! Again thanks for everyone's help !