Execution failed in Android Studio (Error: Execution failed for task ': app: preDexDebug'.)

In the execution of my project the following error is occurring and I already researched in several places, but none solved for my problem. I hope someone can help me.

I've already restarted Android Studio and gave it a Clean, but nothing worked.

  

Error: Execution failed for task ': app: preDexDebug'.

     

com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command' C: \ Program Files \ Java \ jdk1.8.0_45 \ bin \ java.exe '' finished with non-zero exit value 1

build.grad (app):

apply plugin: 'com.android.application'

android {
compileSdkVersion 23
buildToolsVersion "23.0.1"

defaultConfig {
    applicationId "com.example.junior.fireflyapp"
    minSdkVersion 16
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}

dependencies {
     compile 'com.android.support:appcompat-v7:23.1.0'
     compile 'mysql:mysql-connector-java:5.1.37'
     compile 'com.android.support:design:23.1.0'
}

build.grad (project):

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }

    dependencies {
    classpath 'com.android.tools.build:gradle:1.3.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
         jcenter()
    }
}