hibernate - tx.commit() の使用時に例外をスローする Hibernate Delete

Question

Id が 1 つしかない非常に単純な POJO があり、保存と更新が正常に機能しているレコードを削除すると、例外が発生します。commit() を使用しない場合、例外は発生しませんが、使用すると例外が発生します。これがコードです...

public class DeleteCompanyRecords {
public static boolean deleteCompany(String comname){
    Boolean res=false;
    Session session = null;
    String comid=GenCompanyCodeWhenGivenCompanyName.genCompanyCode(comname);
    System.out.println(comid);
    Transaction tx = null;
    try{
        session = SessionCreate.getSessionFactory().openSession();
        tx=(Transaction) session.getTransaction();
        ElitSysCompanyMaster employee = 
                (ElitSysCompanyMaster)session.get(ElitSysCompanyMaster.class, comid); 
        session.delete(employee);res=true;
        session.flush();//tx.commit() also gives exception here.
    }catch (Exception e) {
        session.getTransaction().rollback();
        e.printStackTrace();
        res=false;

    } finally {
        if (session != null)
            if (session.isOpen()){
                session.close();}
    }
    return res;
}

上記のコードでは、tx.commit を使用すると、同じ例外と if(wasCommitted()) ステートメントもスローされます。ガイドしてください。この完全なプロジェクトのために働いているのは私だけです。他に誰もいません。

このテーブルは非常に単純なテーブルで、現時点ではマッピングはありません。例外はそのままです。

  SEVERE: Servlet.service() for servlet [jsp] in context with path [/SecurePass] threw exception [org.hibernate.TransactionException: Transaction not successfully started] with root cause
org.hibernate.TransactionException: Transaction not successfully started
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.rollback(AbstractTransactionImpl.java:202)
    at classes.deleteclasses.DeleteCompanyRecords.deleteCompany(DeleteCompanyRecords.java:25)
    at org.apache.jsp.DeleteRecords.DeleteCompany_jsp._jspService(DeleteCompany_jsp.java:81)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)