compiler errors - I don't know more what to do! (java.lang.NoClassDefFoundError:) -

my application give me error , don't know how solve! i'm using netbeans 8.0.

the error:

exception in thread "main" java.lang.noclassdeffounderror: autenticacao/logon @ bolaofuleco.bolaofuleco.main(bolaofuleco.java:23) caused by: java.lang.classnotfoundexception: autenticacao.logon @ java.net.urlclassloader$1.run(urlclassloader.java:366) @ java.net.urlclassloader$1.run(urlclassloader.java:355) @ java.security.accesscontroller.doprivileged(native method) @ java.net.urlclassloader.findclass(urlclassloader.java:354) @ java.lang.classloader.loadclass(classloader.java:425) @ sun.misc.launcher$appclassloader.loadclass(launcher.java:308) @ java.lang.classloader.loadclass(classloader.java:358) ... 1 more java result: 1 

classes: principal:

package bolaofuleco;  import autenticacao.logon; import javax.swing.jframe;  public class bolaofuleco {     public static void main(string[] args) {         logon login;         login = new logon(new jframe(), true);     }  } 

and when use option clean , build of netbeans appears this:

ant -f c:\\users\\caiocezar\\documents\\netbeansprojects\\bolaofuleco -dnb.internal.action.name=rebuild clean jar init: deps-clean: updating property file: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\built-clean.properties deleting directory c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build clean: init: deps-jar: created dir: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build updating property file: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\built-jar.properties created dir: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\classes created dir: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\empty created dir: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\generated-sources\ap-source-output compiling 17 source files c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\build\classes c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\src\autenticacao\logon.java:207: error: cannot find symbol         if(usuario != null){   symbol:   variable usuario   location: class logon 1 error c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\nbproject\build-impl.xml:923: following error occurred while executing line: c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\nbproject\build-impl.xml:263: compile failed; see compiler error output details. 

your logon class not compiling,

c:\users\caiocezar\documents\netbeansprojects\bolaofuleco\src\autenticacao\logon.java:207: error: cannot find symbol if(usuario != null){ symbol: variable usuario location: class logon

open "src\autenticacao\logon.java" , need fix compiler error there (on line 207). presumably, usuario != null should usuario != null if check (assuming it's field, , following java naming conventions).