How to clean up an ionic project? (MultiDex error) - ionic-framework

Question

hope you can help me out.
I'm having a big issue to run my app on Genymotion emulator and on my real device, it's been a few days since I got stuck on this. The problem is that I'm getting the MultiDex error. I already follow those two steps on
Multidex, I added the multiDexEnabled true line on my build.gradle file and I also add the class from the multidex support library on my Manifest.
After a few hours of search I discovered that I need to clean up my project to prevent it to get over the 65k methods supported by Android (MultiDex error), but (there's always a "but") I'm new on ionic development and I don't know what I can delete and what I can not delete, what's important and what's it's not important.
After a few changes trying to solve it, the error changed from MultiDex to DexDebug, I'm not an expert, but I think it's almost the same. Sorry if I'm wrong about it, it's just a guess.
Can someone help me to understand that and help me to solve this issue?
As I'm not allowed to use images yet, The print screen that shows my project structure, the error, and the emulator (with no sign of the app) is posted here

Answer 1

The error in your posted screenshot says:
java.lang.UnsupportedClassVersionError: com/android/dx/command/Main : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Your com/android/dx/command/Main class (which is part of dx tool) that your build script tries to invoke was compiled with Java 1.8 (major.minor version 52.0), while it is being executed with JDK 1.7 (as you can see in log).
You have two options to fix this error:
Install JDK 1.8 and let Gradle use it (for example, by pointing JAVA_HOME to 1.8's path).
or
Revert buildtools to an older version, for example buildToolsVersion "23.0.2".