Zakommitilsya - fine.
After upgrading from SVN, I started to get an exception that I did not quite understand when compiling, and it swears not only on the mysql-connector , but also on other libraries and the project as a whole, how to. By the machine with which the commit was made - everything works.
Exception :

 Information:15.06.2017 11:12 - Compilation completed with 22 errors and 0 warnings in 3 sec Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] Exception in thread "main" java.lang.reflect.InvocationTargetException Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.reflect.Method.invoke(Method.java:597) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at com.intellij.rt.execution.CommandLineWrapper.main(CommandLineWrapper.java:130) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] Caused by: java.lang.UnsupportedClassVersionError: com/android/dx/command/dexer/Main : Unsupported major.minor version 52.0 Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.ClassLoader.defineClass1(Native Method) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.ClassLoader.defineClass(ClassLoader.java:616) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.net.URLClassLoader.access$000(URLClassLoader.java:58) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.net.URLClassLoader$1.run(URLClassLoader.java:197) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.security.AccessController.doPrivileged(Native Method) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.net.URLClassLoader.findClass(URLClassLoader.java:190) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.ClassLoader.loadClass(ClassLoader.java:307) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at java.lang.ClassLoader.loadClass(ClassLoader.java:248) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at org.jetbrains.android.compiler.tools.AndroidDxRunner.loadDex(AndroidDxRunner.java:75) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at org.jetbrains.android.compiler.tools.AndroidDxRunner.runDex(AndroidDxRunner.java:128) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] at org.jetbrains.android.compiler.tools.AndroidDxRunner.main(AndroidDxRunner.java:294) Error:Android Pre Dex: [mysql-connector-java-5.1.6.jar] ... 5 more

If we remove Pre-Dex from the settings, we get a similar exception :

 Information:15.06.2017 11:25 - Compilation completed with 22 errors and 0 warnings in 3 sec Error:Android Dex: [carwash] Exception in thread "main" java.lang.reflect.InvocationTargetException Error:Android Dex: [carwash] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) Error:Android Dex: [carwash] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) Error:Android Dex: [carwash] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) Error:Android Dex: [carwash] at java.lang.reflect.Method.invoke(Method.java:597) Error:Android Dex: [carwash] at com.intellij.rt.execution.CommandLineWrapper.main(CommandLineWrapper.java:130) Error:Android Dex: [carwash] Caused by: java.lang.UnsupportedClassVersionError: com/android/dx/command/dexer/Main : Unsupported major.minor version 52.0 Error:Android Dex: [carwash] at java.lang.ClassLoader.defineClass1(Native Method) Error:Android Dex: [carwash] at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) Error:Android Dex: [carwash] at java.lang.ClassLoader.defineClass(ClassLoader.java:616) Error:Android Dex: [carwash] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) Error:Android Dex: [carwash] at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) Error:Android Dex: [carwash] at java.net.URLClassLoader.access$000(URLClassLoader.java:58) Error:Android Dex: [carwash] at java.net.URLClassLoader$1.run(URLClassLoader.java:197) Error:Android Dex: [carwash] at java.security.AccessController.doPrivileged(Native Method) Error:Android Dex: [carwash] at java.net.URLClassLoader.findClass(URLClassLoader.java:190) Error:Android Dex: [carwash] at java.lang.ClassLoader.loadClass(ClassLoader.java:307) Error:Android Dex: [carwash] at java.lang.ClassLoader.loadClass(ClassLoader.java:248) Error:Android Dex: [carwash] at org.jetbrains.android.compiler.tools.AndroidDxRunner.loadDex(AndroidDxRunner.java:75) Error:Android Dex: [carwash] at org.jetbrains.android.compiler.tools.AndroidDxRunner.runDex(AndroidDxRunner.java:128) Error:Android Dex: [carwash] at org.jetbrains.android.compiler.tools.AndroidDxRunner.main(AndroidDxRunner.java:294) Error:Android Dex: [carwash] ... 5 more

    2 answers 2

    The error "Unsupported major.minor version 52.0" means that the code corresponds to version 52 ( Java 8 ), but you are trying to build it with the compiler version below.

    Go to the settings and check if the JDK and Android SDK meet the requirements of the compiled project.

    In Android Studio, go to:

    File > Project Structure > SDK Location

    Be sure to check the Use the embedded JDK checkbox.

    Here is the version table for the future:

     Java SE 8 = 52 Java SE 7 = 51 Java SE 6.0 = 50, Java SE 5.0 = 49 JDK 1.4 = 48 JDK 1.3 = 47 JDK 1.2 = 46 JDK 1.1 = 45
    • Yes, thank you, a very important table and I like it as I remember about it! Maybe of course I don’t understand, because This is my first project for a robot, but still; JAVA_HOME: 1.8.0.121 Project SDK: API 19 (java version 1.8.0.121) Project SDK: API 23 (java version 1.8.0.121) Language Level: java 6 if I go up to level 7, it already crashes: 'Error: java: javacTask: source release 1.7 requires target release 1.7 ' I’m probably not going to write about the 8th level, since the robot still has no idea about it at all And that the funniest environment on both machines is the same ... - Alex
    • @Alex, I don’t understand what kind of robot we are talking about, since there was not a word about it. BUT ... JAVA_HOME can be anything. In IDE, you can work in parallel with different projects oriented to different versions of java. - Mikhail Rebrov
    • @Alex, I again don’t know what the robot is guessing, but the error clearly states that you must compile using the JDK with the corresponding version 52 (Java 1.8). - Mikhail Rebrov
    • Please provide a screenshot of this menu: File > Project Structure > SDK Location in question. - Mikhail Rebrov
    • @Alex, Java 6 was released in 2006, while Android appeared in 2009, I’m not about API 19 - Mikhail Rebrov

    Michael was right, there really was a problem with setting 1.6 - 1.8, but even when I changed everywhere by 1.8, it automatically flew or threw out actions.

    All problems solved by completely reinstalling the SDK . using the old installer android-installer_r22.0.5-windows and the subsequent update. PS / At least assembled the project and launched.