Convert classes into dex format. pls help

So i try to get my Unity project from my Pc to my Android tablet when this error comes up. Anyone know what i should do???

CommandInvokationFailure: Unable to convert classes into dex format.
D:/Jdk\bin\java.exe -Xmx1024M -Dcom.android.sdkmanager.toolsdir=“D:/AN_SDK\tools” -Dfile.encoding=UTF8 -jar “D:\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar” -

stderr[
Exception in thread “main” 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(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at SDKMain.main(SDKMain.java:127)
]
stdout[

]
UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)

UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[ ] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)

UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[ ] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)

UnityEditor.HostView:OnGUI()

You should install JDK 8 and point Unity to use it (under Preferences → external tools)