Java. lang. IllegalArgumentException: already added: Lorg/apache/poi/encryptedincluentexception;

Java. lang. IllegalArgumentException: already added: Lorg/apache/poi/encryptedincluentexception;
[11:38:23-RollCallSystem] Dx at com. android. dx. dex. file. ClassDefsSection. add (ClassDefsSection. java: 123)
[11:38:23-RollCallSystem] Dx at com. android. dx. dex. file. DexFile. add (DexFile. java: 143)
[11:38:23-RollCallSystem] Dx at com. android. dx. command. dexer. Main. processClass (Main. java: 372)
[11:38:23-RollCallSystem] Dx at com. android. dx. command. dexer. Main. processFileBytes (Main. java: 346)
[11:38:23-RollCallSystem] Dx at com. android. dx. command. dexer. Main. access $400 (Main. java: 59)
[11:38:23-RollCallSystem] Dx at com. android. dx. command. dexer. Main $1. processFileBytes (Main. java: 294)
[11:38:23-RollCallSystem] Dx at com. android. dx. cf. direct. ClassPathOpener. processArchive (ClassPathOpener. java: 244)
[11:38:23-rollcallsystem] dx at com. Android. dx. Cf. Direct. classpathopener. processone (classpathopener. Java: 130)
[11:38:23-rollcallsystem] dx at com. Android. dx. Cf. Direct. classpathopener. Process (classpathopener. Java: 108)
[11:38:23-rollcallsystem] dx at com. Android. dx. Command. dexer. Main. processone (main. Java: 313)
[11:38:23-rollcallsystem] dx at com. Android. dx. Command. dexer. Main. processallfiles (main. Java: 233)
[11:38:23-rollcallsystem] dx at com. Android. dx. Command. dexer. Main. Run (main. Java: 185)
[11:38:23-rollcallsystem] dx at Sun. Reflect. generatedmethodaccessor13.invoke (unknown source)
[11:38:23-rollcallsystem] dx at Sun. Reflect. delegatingmethodaccessorimpl. Invoke (delegatingmethodaccessorimpl. Java: 25)
[11:38:23-RollCallSystem] Dx at java. lang. reflect. Method. invoke (Method. java: 585)
[11:38:23-RollCallSystem] Dx at com. android. ide. eclipse. adt. internal. build. DexWrapper. run (DexWrapper. java: 179)
[11:38:23-RollCallSystem] Dx at com.android.ide.eclipse.adt.internal.build.BuildHelper.exe cuteDx (BuildHelper. java: 585)
[11:38:23-RollCallSystem] Dx at com. android. ide. eclipse. adt. internal. build. builders. PostCompilerBuilder. build (PostCompilerBuilder. java: 490)
[11:38:23-RollCallSystem] Dx at org. eclipse. core. internal. events. BuildManager $ 2.run( BuildManager. java: 629)
[11:38:23-RollCallSystem] Dx at org. eclipse. core. runtime. SafeRunner. run (SafeRunner. java: 42)
[11:38:23-RollCallSystem] Dx at org. eclipse. core. internal. events. BuildManager. basicBuild (BuildManager. java: 172)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. buildmanager. basicbuild (buildmanager. Java: 203)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. buildmanager $ 1.run( buildmanager. Java: 255)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. runtime. saferunner. Run (saferunner. Java: 42)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. buildmanager. basicbuild (buildmanager. Java: 258)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. buildmanager. basicbuildloop (buildmanager. Java: 311)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. buildmanager. Build (buildmanager. Java: 343)
[11:38:23-rollcallsystem] dx at org. Eclipse. Core. Internal. Events. autobuildjob. dobuild (autobuildjob. Java: 144)
[11:38:23-RollCallSystem] Dx at org. eclipse. core. internal. events. AutoBuildJob. run (AutoBuildJob. java: 242)
[11:38:23-RollCallSystem] Dx at org.eclipse.core.internal.jobs. Worker. run (Worker. java: 54)
[11:38:23-RollCallSystem] Dx 1 error; aborting
[11:38:23-RollCallSystem] Conversion to Dalvik format failed with error 1

Cause: Package reference Problems

Solution: you cannot directly put the jar package in the android project. If you want to import the package through external reference, there will be no conflict.