Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: javax.swing.JButton -

i need solve error.

the window need register beer not openning.

i'm creating simple system can register , search beer's aparrently.

here code.

package cadastro;  import java.awt.container; import java.awt.gridlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener; import java.io.file; import java.io.ioexception; import javax.swing.jbutton; import javax.swing.jframe;   public class entrada extends jframe {  private static final long serialversionuid = 42l; private final container container; private final jbutton btcadastrar; private final jbutton btpesquisar; private final jbutton btsair;  public entrada() {      super("sistema de avaliação de cervejas");     container = getcontentpane();     container.setlayout(new gridlayout(0,1));     gerenciadorbotoes btmanager = new gerenciadorbotoes();      btcadastrar = new jbutton();       btpesquisar = new jbutton();     btsair = new jbutton();      btcadastrar.settext("cadastrar cervejas");     btcadastrar.setactioncommand("1");     btpesquisar.settext("pesquisar cervejas");     btpesquisar.setactioncommand("2");     btsair.settext("sair");     btsair.setactioncommand("3");      btcadastrar.addactionlistener(btmanager);     btpesquisar.addactionlistener(btmanager);     btsair.addactionlistener(btmanager);      container.add(btcadastrar);     container.add(btpesquisar);     container.add(btsair);      setdefaultcloseoperation(jframe.exit_on_close);  setbounds(new java.awt.rectangle(300, 150, 0, 0));      setsize(300, 200); setresizable(false);  }  private class gerenciadorbotoes implements actionlistener {       @override     public void actionperformed(actionevent e) {         if (null != e.getactioncommand()) {             if ("1".equals(e.getactioncommand())) {                 new cadastra().setvisible(true);             } else {                 if ("2".equals(e.getactioncommand())) {                     new pesquisar().setvisible(true);                 }                 else {                 }             }         }     } }  static void abrir() { try {         acervo.getinstance().open(new file("agenda.poo")); } catch (ioexception | classnotfoundexception e) { } }  public static void main(string args[]) { entrada.abrir(); java.awt.eventqueue.invokelater(new runnable() {         @override         public void run() {     new entrada().setvisible(true);         } }); } 

}

and here other.

package cadastro;  import javax.swing.jframe; import javax.swing.jbutton; import javax.swing.jlabel; import javax.swing.jscrollpane; import javax.swing.jcombobox; import javax.swing.jtextarea; import javax.swing.jtextfield; import javax.swing.joptionpane;   public class cadastra extends jframe {  private final int id = 0;  private jbutton btcadastrar; private jbutton btlimpar; private jlabel lbnome; private jlabel lbempresa; private jlabel lbtipo; private jlabel lbnota; private jlabel lbcomentario; private jscrollpane scrollcoment; private jcombobox cbnota; private jtextarea tfcomentario; private jtextfield tfempresa; private jtextfield tftipo; private jtextfield tfnome;  public cadastra() {     initcomponents(); }  private void initcomponents() {      lbnome = new jlabel();     tfnome = new jtextfield();     lbempresa = new jlabel();     tfempresa = new jtextfield();     lbtipo = new jlabel();     tftipo = new jtextfield();     lbnota = new jlabel();     lbcomentario = new jlabel();     scrollcoment = new jscrollpane();     tfcomentario = new jtextarea();     cbnota = new jcombobox();     btcadastrar = new jbutton();     btlimpar = new jbutton();      setdefaultcloseoperation(javax.swing.windowconstants.dispose_on_close);     settitle("cadastrar");     setbounds(new java.awt.rectangle(300, 150, 0, 0));     setpreferredsize(new java.awt.dimension(700, 452));     setresizable(false);     addwindowlistener(new java.awt.event.windowadapter() {          @override         public void windowclosing(java.awt.event.windowevent evt) {             windowclose(evt);         }     });      lbnome.settext("nome da cerveja");     lbempresa.settext("empresa");      tfempresa.addactionlistener(new java.awt.event.actionlistener() {         @override         public void actionperformed(java.awt.event.actionevent evt) {             txtnaactionperformed(evt);         }     });      lbtipo.settext("tipo");     lbnota.settext("nota");     lbcomentario.settext("comentário");      tfcomentario.setcolumns(20);     tfcomentario.setrows(5);     scrollcoment.setviewportview(tfcomentario);      cbnota.setmodel(new javax.swing.defaultcomboboxmodel(new string[]{"1", "2", "3", "4", "5", "6", "7", "8", "9", "10"}));     cbnota.addactionlistener(new java.awt.event.actionlistener() {         @override         public void actionperformed(java.awt.event.actionevent evt) {             notaactionperformed(evt);         }     });      btcadastrar.settext("cadastrar");     btcadastrar.addactionlistener(new java.awt.event.actionlistener() {         @override         public void actionperformed(java.awt.event.actionevent evt) {             jbutton1actionperformed(evt);         }     });      btlimpar.settext("limpar");     btlimpar.addactionlistener(new java.awt.event.actionlistener() {         @override         public void actionperformed(java.awt.event.actionevent evt) {             jbutton2actionperformed(evt);         }     });      javax.swing.grouplayout layout = new javax.swing.grouplayout(getcontentpane());     getcontentpane().setlayout(layout);     layout.sethorizontalgroup(             layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                     .addgroup(layout.createsequentialgroup()                             .addcontainergap()                             .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                                     .addgroup(layout.createsequentialgroup()                                             .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading).                                                     addgroup(layout.createsequentialgroup()                                                             .addcomponent(lbnome)                                                             .addgap(18, 18, 18)                                                             .addcomponent(tfnome, javax.swing.grouplayout.preferred_size, 130, javax.swing.grouplayout.preferred_size))                                                     .addgroup(layout.createsequentialgroup()                                                             .addcomponent(lbtipo)                                                             .addgap(18, 18, 18)                                                             .addcomponent(tftipo, javax.swing.grouplayout.preferred_size, 130, javax.swing.grouplayout.preferred_size)))                                             .addgap(79, 79, 79)                                             .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                                                     .addgroup(layout.createsequentialgroup()                                                             .addcomponent(lbnota)                                                             .addgap(18, 18, 18)                                                             .addcomponent(cbnota, javax.swing.grouplayout.preferred_size, javax.swing.grouplayout.default_size, javax.swing.grouplayout.preferred_size)                                                             .addgap(173, 173, 173))                                                     .addgroup(layout.createsequentialgroup()                                                             .addcomponent(lbempresa)                                                             .addpreferredgap(javax.swing.layoutstyle.componentplacement.unrelated)                                                             .addcomponent(tfempresa, javax.swing.grouplayout.default_size, 149, short.max_value)                                                             .addcontainergap())))                                     .addgroup(layout.createsequentialgroup()                                             .addcomponent(lbcomentario)                                             .addpreferredgap(javax.swing.layoutstyle.componentplacement.related)                                             .addcomponent(scrollcoment)                                             .addgap(18, 18, 18)                                             .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                                                     .addcomponent(lbempresa)                                                     .addcomponent(lbnome))                                             .addgap(82, 82, 82)))));     layout.linksize(javax.swing.swingconstants.horizontal, new java.awt.component[]{btcadastrar, btlimpar});     layout.setverticalgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)             .addgroup(layout.createsequentialgroup()                     .addcontainergap()                     .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.baseline)                             .addcomponent(lbnome)                             .addcomponent(tfnome, javax.swing.grouplayout.preferred_size, javax.swing.grouplayout.default_size, javax.swing.grouplayout.preferred_size)                             .addcomponent(lbempresa)                             .addcomponent(tfempresa, javax.swing.grouplayout.preferred_size, javax.swing.grouplayout.default_size, javax.swing.grouplayout.preferred_size))                     .addgap(26, 26, 26)                     .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.baseline)                             .addcomponent(lbtipo)                             .addcomponent(tftipo, javax.swing.grouplayout.preferred_size, javax.swing.grouplayout.default_size, javax.swing.grouplayout.preferred_size)                             .addcomponent(lbnota)                             .addcomponent(cbnota, javax.swing.grouplayout.preferred_size, javax.swing.grouplayout.default_size, javax.swing.grouplayout.preferred_size))                     .addgap(30, 30, 30)                     .addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                             .addcomponent(lbcomentario)                             .addgroup(layout.createsequentialgroup()                                     .addgap(25, 25, 25)                                     .addcomponent(btcadastrar)                                     .addgap(30, 30, 30)                                     .addcomponent(btlimpar))                             .addcomponent(scrollcoment, javax.swing.grouplayout.preferred_size, 125, javax.swing.grouplayout.preferred_size))                     .addcontainergap(150, short.max_value)));     pack(); }  private void notaactionperformed(java.awt.event.actionevent evt) {     // }  private void jbutton2actionperformed(java.awt.event.actionevent evt) { // apaga os caracteres escritos                                          tfnome.settext("");     tfempresa.settext("");     tftipo.settext("");     tfcomentario.settext("");     cbnota.setselectedindex(0); }  private void jbutton1actionperformed(java.awt.event.actionevent evt) { // gravar os dados cadastrados      string nome = tfnome.gettext();     string nomeempresa = tfempresa.gettext();     string tipo = tftipo.gettext();     string comentario = tfcomentario.gettext();     int selecionado = cbnota.getselectedindex();     string snota = integer.tostring(selecionado + 1);      if (nome == null || nome.trim().equals("")) { // se o nome null ou o nome, retirando os espaços em branco, igual ""         joptionpane.showmessagedialog(this, "não foi possível adicionar. forneça o nome da cerveja!", "erro", joptionpane.error_message);     } else {         boolean temcerveja = acervo.getinstance().temcerveja(nome);         if (temcerveja) {         joptionpane.showmessagedialog(this, "não foi possível adicionar. cerveja com mesmo nome já cadastrado!", "aviso", joptionpane.warning_message);         } else {         cervejaatual cerveja = new cervejaatual(nome ,nomeempresa,tipo , comentario, snota);         acervo acervo = acervo.getinstance();         acervo.addcerveja(cerveja);          joptionpane.showmessagedialog(this, "adicionado com sucesso!", "informação", joptionpane.information_message);         this.dispose();         }     }    }  private void txtnaactionperformed(java.awt.event.actionevent evt) {  }  private void windowclose(java.awt.event.windowevent evt) {  } 

}

the error.

exception in thread "awt-eventqueue-0" java.lang.illegalstateexception: javax.swing.jbutton[,0,0,0x0,invalid,alignmentx=0.0,alignmenty=0.5,border=javax.swing.plaf.borderuiresource$compoundborderuiresource@7e83ef0,flags=296,maximumsize=,minimumsize=,preferredsize=,defaulticon=,disabledicon=,disabledselectedicon=,margin=javax.swing.plaf.insetsuiresource[top=2,left=14,bottom=2,right=14],paintborder=true,paintfocus=true,pressedicon=,rolloverenabled=true,rollovericon=,rolloverselectedicon=,selectedicon=,text=limpar,defaultcapable=true] not attached horizontal group @ javax.swing.grouplayout.checkcomponents(grouplayout.java:1086) @ javax.swing.grouplayout.prepare(grouplayout.java:1040) @ javax.swing.grouplayout.layoutcontainer(grouplayout.java:910) @ java.awt.container.layout(container.java:1510) @ java.awt.container.dolayout(container.java:1499) @ java.awt.container.validatetree(container.java:1695) @ java.awt.container.validatetree(container.java:1704) @ java.awt.container.validatetree(container.java:1704) @ java.awt.container.validatetree(container.java:1704) @ java.awt.container.validate(container.java:1630) @ java.awt.container.validateunconditionally(container.java:1667) @ java.awt.window.pack(window.java:818) @ cadastro.cadastra.initcomponents(cadastra.java:173) @ cadastro.cadastra.<init>(cadastra.java:36) @ cadastro.entrada$gerenciadorbotoes.actionperformed(entrada.java:66) @ javax.swing.abstractbutton.fireactionperformed(abstractbutton.java:2022) @ javax.swing.abstractbutton$handler.actionperformed(abstractbutton.java:2348) @ javax.swing.defaultbuttonmodel.fireactionperformed(defaultbuttonmodel.java:402) @ javax.swing.defaultbuttonmodel.setpressed(defaultbuttonmodel.java:259) @ javax.swing.plaf.basic.basicbuttonlistener.mousereleased(basicbuttonlistener.java:252) @ java.awt.component.processmouseevent(component.java:6535) @ javax.swing.jcomponent.processmouseevent(jcomponent.java:3324) @ java.awt.component.processevent(component.java:6300) @ java.awt.container.processevent(container.java:2236) @ java.awt.component.dispatcheventimpl(component.java:4891) @ java.awt.container.dispatcheventimpl(container.java:2294) @ java.awt.component.dispatchevent(component.java:4713) @ java.awt.lightweightdispatcher.retargetmouseevent(container.java:4888) @ java.awt.lightweightdispatcher.processmouseevent(container.java:4525) @ java.awt.lightweightdispatcher.dispatchevent(container.java:4466) @ java.awt.container.dispatcheventimpl(container.java:2280) @ java.awt.window.dispatcheventimpl(window.java:2750) @ java.awt.component.dispatchevent(component.java:4713) @ java.awt.eventqueue.dispatcheventimpl(eventqueue.java:758) @ java.awt.eventqueue.access$500(eventqueue.java:97) @ java.awt.eventqueue$3.run(eventqueue.java:709) @ java.awt.eventqueue$3.run(eventqueue.java:703) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$javasecurityaccessimpl.dointersectionprivilege(protectiondomain.java:76) @ java.security.protectiondomain$javasecurityaccessimpl.dointersectionprivilege(protectiondomain.java:86) @ java.awt.eventqueue$4.run(eventqueue.java:731) @ java.awt.eventqueue$4.run(eventqueue.java:729) @ java.security.accesscontroller.doprivileged(native method) @ java.security.protectiondomain$javasecurityaccessimpl.dointersectionprivilege(protectiondomain.java:76) @ java.awt.eventqueue.dispatchevent(eventqueue.java:728) @ java.awt.eventdispatchthread.pumponeeventforfilters(eventdispatchthread.java:201) @ java.awt.eventdispatchthread.pumpeventsforfilter(eventdispatchthread.java:116) @ java.awt.eventdispatchthread.pumpeventsforhierarchy(eventdispatchthread.java:105) @ java.awt.eventdispatchthread.pumpevents(eventdispatchthread.java:101) @ java.awt.eventdispatchthread.pumpevents(eventdispatchthread.java:93) @ java.awt.eventdispatchthread.run(eventdispatchthread.java:82) 

these lines:

.addgroup(layout.createparallelgroup(javax.swing.grouplayout.alignment.leading)                                                 .addcomponent(lbempresa)                                                 .addcomponent(lbnome)) 

and these lines:

               .addgroup(layout.createsequentialgroup()                             .addgap(25, 25, 25)                             .addcomponent(btcadastrar)                             .addgap(30, 30, 30)                             .addcomponent(btlimpar)) 

you have change lbempresa , lbnome btcadastrar , btlimpar.