Hibernate ConstraintViolationException

In following code (a JUnit test method) I’m trying to delete specified users from database

 

But when running above code, I got following exception:

org.hibernate.exception.ConstraintViolationException: could not execute batch

at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:129)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.performExecution(BatchingBatch.java:132)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.doExecuteBatch(BatchingBatch.java:111)
at org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl.execute(AbstractBatchImpl.java:163)
at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.executeBatch(JdbcCoordinatorImpl.java:226)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:484)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:351)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:350)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1222)
at com.dfweb.service.impl.SysUserServiceImplTest.testAddPermissions(SysUserServiceImplTest.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Caused by: java.sql.BatchUpdateException: Cannot delete or update a parent row: a foreign key constraint fails (db_df.permission_sys_user, CONSTRAINT FK_2l5pbq5juqkbrg6rtqes6w1el FOREIGN KEY (users_id) REFERENCES sys_user (id))
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:2055)
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1467)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1135)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.performExecution(BatchingBatch.java:123)
… 41 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (db_df.permission_sys_user, CONSTRAINT FK_2l5pbq5juqkbrg6rtqes6w1el FOREIGN KEY (users_id) REFERENCES sys_user (id))
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1041)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4237)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4169)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2617)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2778)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2441)
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:2007)
… 44 more

 

Reason

This is because there is an RESTRICT reference for foreign key of permission_sys_user that references id column of sys_user table.

So deleting the SysUser entity and keep its related permissions in permission_sys_user table will break the foreign key constraint of permission_sys_user table (references sys_user table with default RESTRICT reference option).

 

Solution

Following is SysUser class related source code

 

One possible solution is to remove its related records in permission_sys_user table when deleting SysUser entity, so change SysUser to following will fix this issue:

Above code adds CascadeType.REMOVE  for ManyToMany  annotation’s cascade  attribute. This will make deleting SysUser entity will trigger deleting related Permission entities.

java.lang.NoSuchMethodError: com.google.common.collect.ImmutableSet.toImmutableSet

Recently I tried to use Selenium for Web UI auto testing, but when running driver.get()  function, I got following error

java.lang.NoSuchMethodError: com.google.common.collect.ImmutableSet.toImmutableSet()Ljava/util/stream/Collector;

 

Following is full stacktrace

Starting ChromeDriver 2.29.461591 (62ebf098771772160f391d75e589dc567915b233) on port 20686
Only local connections are allowed.

java.lang.NoSuchMethodError: com.google.common.collect.ImmutableSet.toImmutableSet()Ljava/util/stream/Collector;

at org.openqa.selenium.remote.ProtocolHandshake.streamW3CProtocolParameters(ProtocolHandshake.java:238)
at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:104)
at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:141)
at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:82)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:604)
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:244)
at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:131)
at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:144)
at org.openqa.selenium.chrome.ChromeDriver.<init>(ChromeDriver.java:178)
at org.openqa.selenium.chrome.ChromeDriver.<init>(ChromeDriver.java:167)
at org.openqa.selenium.chrome.ChromeDriver.<init>(ChromeDriver.java:124)
at com.dfweb.service.impl.PaymentLogServiceImplTest.testCalcuateProfitWithDifferentAgentAndUserOfInventory(PaymentLogServiceImplTest.java:43)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Suppressed: java.io.IOException: Incomplete document
at com.google.gson.stream.JsonWriter.close(JsonWriter.java:527)
at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:121)
… 37 more

 

Cause

I look through the com.google.guava jar source code, and found there is com.google.common.collect.ImmutableSet class existed, but there is no toImmutableSet() method defined.

It’s because ImmutableSet.toImmutableSet() method is introduced in Guava version 21.0, while I’m using version 20.0.

 

Solution

My current pom.xml

 

Change version to 21.0 and run mvn install  will fix this issue.

 

IKVM.NET Convert JAR to .NET (C#, VB.NET) DLL

Why Convert JAR to .NET DLL

Imagine your company builds an online file converter, and its backend programming language is Java because of its position in web development. And in this project you build a file parsing library (jar format certainly) which is used to parse different types of files.

After this project is done, your boss decides to create a Windows desktop version for this software. Now the best choice is .NET, but how can you reuse your java parsing library? That’s why IKVM.NET existed.

IKVM.NET Introduction

IKVM.NET is a .NET implementation of Java which allows us to run Java code in .NET (C#, VB.NET, etc.) easily. It includes following three components:

  • JVM in .NET (which means you can run java byte code in .NET)
  • Java class library implementation
  • A compiler converting java byte code to .NET IL

There are many famous Java projects converted to .NET using IKVM.NET already, such as Tika, Curator, etc. Even Mono has include it as a built-in component.

Start Converting

This will generate a DLL file named libpst.dll from libpst.jar in current directory.

Without -target:library option, it will generate an exe file.

 

WebServlet cannot be resolved to a type

WebServlet annotation is introduced in Servlet 3.0, it’s used to simplify the servlet creation (we don’t need to define it and its URL mapping in web.xml)

The WebServlet annotation usage is

e.g.

Then the user can visit /servlet/GetMailFileOwner to access this servlet

 

But today I met a problem with using WebServlet annotation. First I added WebServlet on the Linux machine (Eclipse Luna), and switched to another Windows machine (MyEclipse), then I tried to rebuild the project, I got following error:

On the Windows machine, I use the default servlet.jar which is added when I create the new Dynamic Web Project. But I replaced the default servlet.jar file with Tomcat 8.0 libraries.

So the solution is to add Tomcat 8.0 libraries to Java Build Path (We need first download Tomcat 8.0 and set it up for Eclipse, otherwise Eclipse will not find this Tomcat 8.0 libraries)

Make a Controller method non-action in Play framework 1.2

We create action method for Controller by using public static void

Whether this method is defined in routes file or not, it will be regarded as an action by Play.

 

And there’s another problem: passing parameters by calling action method directly will be impossible

The above uploading function will not work, Because the file parameter in basicUpload function is always null (But the file parameter in upload function is not null)

 

To solve this problem, we need to change the access modifier from public to private

Now the file parameter in basicUpload function will be valid