Java 为什么我不能更改一个实例？

我有以下课程：

public class Finance {
    private User user;

    private ArrayList<account> account;
    private ArrayList<Categorie> categorie;
    private ArrayList<salary> salary;

    private static final Finance instance=new GestaoFinancas();
    public static Finance getFinance() {
        return instance;
    }

    private Finance() {
        user=new User();
        account=new ArrayList<>();
        categorie=new ArrayList<>();
        salary=new ArrayList<>();

        categorie.add(new Categoria("Food"));
        categorie.add(new Categoria("Sleep"));
        categorie.add(new Categoria("Fun"));
    }

    public void setUser(User user) {
        this.user = user;
    }
}

我的问题是如何给一个新用户，以及我应该写Finance.getFinance还是getFinance？每次我尝试为Finance提供新用户时，都会出现以下错误：

Exception in thread "AWT-EventQueue-0" java.lang.ExceptionInInitializerError
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.jButton2ActionPerformed(DadosUtilizador.java:127)
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.access$200(DadosUtilizador.java:14)
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador$3.actionPerformed(DadosUtilizador.java:72)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:109)
at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:184)
at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:229)
at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:227)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:227)
at java.awt.Dialog.show(Dialog.java:1084)
at java.awt.Component.show(Component.java:1671)
at java.awt.Component.setVisible(Component.java:1623)
at java.awt.Window.setVisible(Window.java:1014)
at java.awt.Dialog.setVisible(Dialog.java:1005)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais.btnAlterarUtilizadorActionPerformed(FinancasPessoais.java:174)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais.access$000(FinancasPessoais.java:13)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais$1.actionPerformed(FinancasPessoais.java:51)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: java.lang.UnsupportedOperationException: Not supported yet.
    at pt.ipleiria.estg.es1.financaspessoais.modelo.Utilizador.<init>(Utilizador.java:21)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<init>(GestaoFinancas.java:26)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<clinit>(GestaoFinancas.java:20)

线程“AWT-EventQueue-0”java.lang.ExceptionInInitializeError中的异常 在pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.jButton2ActionPerformed（DadosUtilizador.java:127） 在pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.access$200（DadosUtilizador.java:14） 在pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador$3.actionPerformed（DadosUtilizador.java:72） 在javax.swing.AbstractButton.fireActionPerformed（AbstractButton.java:2022） 位于javax.swing.AbstractButton$Handler.actionPerformed（AbstractButton.java:2348） 在javax.swing.DefaultButtonModel.fireActionPerformed上（DefaultButtonModel.java:402） 在javax.swing.DefaultButtonModel.setPressed中（DefaultButtonModel.java:259） 在javax.swing.plaf.basic.BasicButtonListener.MouseRelease（BasicButtonListener.java:252） 在java.awt.Component.processMouseeEvent（Component.java:6533） 位于javax.swing.JComponent.ProcessMouseeEvent（JComponent.java:3324） 位于java.awt.Component.processEvent（Component.java:6298） 位于java.awt.Container.processEvent（Container.java:2236） 位于java.awt.Component.dispatchEventImpl（Component.java:4889） 位于java.awt.Container.dispatchEventImpl（Container.java:2294） 位于java.awt.Component.dispatchEvent（Component.java:4711） 位于java.awt.LightweightDispatcher.RetargetMouseeEvent（Container.java:4888） 位于java.awt.LightweightDispatcher.ProcessMouseeEvent（Container.java:4525） 在java.awt.LightweightDispatcher.dispatchEvent（Container.java:4466） 位于java.awt.Container.dispatchEventImpl（Container.java:2280） 位于java.awt.Window.dispatchEventImpl（Window.java:2746） 位于java.awt.Component.dispatchEvent（Component.java:4711） 位于java.awt.EventQueue.dispatchEventImpl（EventQueue.java:758） 在java.awt.EventQueue.access$500（EventQueue.java:97） 在java.awt.EventQueue$3.run（EventQueue.java:709） 在java.awt.EventQueue$3.run（EventQueue.java:703） 位于java.security.AccessController.doPrivileged（本机方法） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:80） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:90） 在java.awt.EventQueue$4.run（EventQueue.java:731） 在java.awt.EventQueue$4.run（EventQueue.java:729） 位于java.security.AccessController.doPrivileged（本机方法） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:80） 位于java.awt.EventQueue.dispatchEvent（EventQueue.java:728） 位于java.awt.EventDispatchThread.pumpOneEventForFilters（EventDispatchThread.java:201） 在java.awt.EventDispatchThread.pumpEventsForFilter（EventDispatchThread.java:116）中 在java.awt.EventDispatchThread.pumpEventsForFilter（EventDispatchThread.java:109）中 WaitDispatchSupport$2.run（WaitDispatchSupport.java:184） WaitDispatchSupport$4.run（WaitDispatchSupport.java:229） WaitDispatchSupport$4.run（WaitDispatchSupport.java:227） 位于java.security.AccessController.doPrivileged（本机方法） 在java.awt.WaitDispatchSupport.enter（WaitDispatchSupport.java:227） 在java.awt.Dialog.show（Dialog.java:1084） 在java.awt.Component.show（Component.java:1671） 位于java.awt.Component.setVisible（Component.java:1623） 位于java.awt.Window.setVisible（Window.java:1014） 位于java.awt.Dialog.setVisible（Dialog.java:1005） 在pt.ipleiria.estg.es1.financaspessoais.vista.financaspessoais.btnalterarutilizadoActionPerformed（financaspessoais.java:174） 在pt.ipleiria.estg.es1.financaspessoais.vista.financaspessoais.access$000（financaspessoais.java:13） 在pt.ipleiria.estg.es1.financaspessoais.vista.financaspessoais$1.actionPerformed（financaspessoais.java:51） 在javax.swing.AbstractButton.fireActionPerformed（AbstractButton.java:2022） 位于javax.swing.AbstractButton$Handler.actionPerformed（AbstractButton.java:2348） 在javax.swing.DefaultButtonModel.fireActionPerformed上（DefaultButtonModel.java:402） 在javax.swing.DefaultButtonModel.setPressed中（DefaultButtonModel.java:259） 在javax.swing.plaf.basic.BasicButtonListener.MouseRelease（BasicButtonListener.java:252） 位于java.awt.Component.ProcessMouseeEvent（Component.java:6533） 位于javax.swing.JComponent.ProcessMouseeEvent（JComponent.java:3324） 位于java.awt.Component.processEvent（Component.java:6298） 位于java.awt.Container.processEvent（Container.java:2236） 位于java.awt.Component.dispatchEventImpl（Component.java:4889） 位于java.awt.Container.dispatchEventImpl（Container.java:2294） 位于java.awt.Component.dispatchEvent（Component.java:4711） 位于java.awt.LightweightDispatcher.RetargetMouseeEvent（Container.java:4888） 位于java.awt.LightweightDispatcher.ProcessMouseeEvent（Container.java:4525） 位于java.awt.LightweightDispatcher.dispatchEvent（Container.java:4466） 位于java.awt.Container.dispatchEventImpl（Container.java:2280） 位于java.awt.Window.dispatchEventImpl（Window.java:2746） 位于java.awt.Component.dispatchEvent（Component.java:4711） 位于java.awt.EventQueue.dispatchEventImpl（EventQueue.java:758） 在java.awt.EventQueue.access$500（EventQueue.java:97） 在java.awt.EventQueue$3.run（EventQueue.java:709） 在java.awt.EventQueue$3.run（EventQueue.java:703） 位于java.security.AccessController.doPrivileged（本机方法） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:80） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:90） 在java.awt.EventQueue$4.run（EventQueue.java:731） 在java.awt.EventQueue$4.run（EventQueue.java:729） 位于java.security.AccessController.doPrivileged（本机方法） 位于java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:80） 位于java.awt.EventQueue.dispatchEvent（EventQueue.java:728） 位于java.awt.EventDispatchThread.pumpOneEventForFilters（EventDispatchThread.java:201） 在java.awt.EventDispatchThread.pumpEventsForFilter（Eve

Exception in thread "AWT-EventQueue-0" java.lang.ExceptionInInitializerError
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.jButton2ActionPerformed(DadosUtilizador.java:127)
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador.access$200(DadosUtilizador.java:14)
at pt.ipleiria.estg.es1.financaspessoais.vista.DadosUtilizador$3.actionPerformed(DadosUtilizador.java:72)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:109)
at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:184)
at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:229)
at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:227)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:227)
at java.awt.Dialog.show(Dialog.java:1084)
at java.awt.Component.show(Component.java:1671)
at java.awt.Component.setVisible(Component.java:1623)
at java.awt.Window.setVisible(Window.java:1014)
at java.awt.Dialog.setVisible(Dialog.java:1005)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais.btnAlterarUtilizadorActionPerformed(FinancasPessoais.java:174)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais.access$000(FinancasPessoais.java:13)
at pt.ipleiria.estg.es1.financaspessoais.vista.FinancasPessoais$1.actionPerformed(FinancasPessoais.java:51)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: java.lang.UnsupportedOperationException: Not supported yet.
    at pt.ipleiria.estg.es1.financaspessoais.modelo.Utilizador.<init>(Utilizador.java:21)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<init>(GestaoFinancas.java:26)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<clinit>(GestaoFinancas.java:20)

Caused by: java.lang.UnsupportedOperationException: Not supported yet.
    at pt.ipleiria.estg.es1.financaspessoais.modelo.Utilizador.<init>(Utilizador.java:21)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<init>(GestaoFinancas.java:26)
    at pt.ipleiria.estg.es1.financaspessoais.modelo.GestaoFinancas.<clinit>(GestaoFinancas.java:20)