Question Whose end is this error on?

This error occurs when trying to run my projects on my mac laptop.

Code (Text):

1. [Debug] Java Home: /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre
2. [Debug] Java Version: 8u121 x64 (Oracle Corporation)
3. [Debug] RuneMate Version: 2.5.0
4. [Debug] Operating System: Mac OS X x64
5. Exception in Application start method
6. Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
7.     at nul.iiiiiIiiiIiI.float(ena:11815)
8.     at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
9.     at java.security.AccessController.doPrivileged(Native Method)
10.     at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
11.     at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
12. Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
13.     at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
14.     at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
15.     at java.lang.Thread.run(Thread.java:745)
16. Caused by: java.lang.NoSuchMethodError: sun.jvmstat.perfdata.monitor.CountedTimerTaskUtils.this(Ljava/lang/String;)Ljava/lang/String;
17.     at nul.IIIiiiIIiiiI.<clinit>(uub:216)
18.     at nul.iIIIIiIiIiiI.this(uub:13884)
19.     at nul.iiiiiiIiIIIi.<init>(fu:303)
20.     at nul.IIiIiiIiiiII.<init>(fu:21694)
21.     at nul.iIIIIiIiIiiI.this(uub:11149)
22.     at nul.IiiiIIiIIIii.<init>(npb:180)
23.     at nul.IiiIiIiiiIII.<clinit>(bqb:162)
24.     at nul.iiIiiIiiIiii.<clinit>(spa:218)
25.     at nul.iiiiiIiiiIiI.initialize(ena:16218)
26.     at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
27.     at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
28.     at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
29.     at nul.iIiiiIiIIiII.this(mma:144)
30.     at nul.iIiiiIiIIiII.<init>(mma:79)
31.     at nul.iIiiiIiIIiII.<init>(mma:155)
32.     at nul.iiiiiIiiiIiI.<init>(ena:32)
33.     at nul.iiiiiIiiiIiI.this(ena:15828)
34.     at com.runemate.boot.Boot.start(gmb:100)
35.     at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
36.     at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
37.     at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
38.     at java.security.AccessController.doPrivileged(Native Method)
39.     at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
40.     at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
41.