this is my gradle file
apply plugin: 'com.android.application'
android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"
defaultConfig {
    applicationId "com.example.myapplication"
    minSdkVersion 15
    targetSdkVersion 22
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}
dependencies{
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:23.0.0'
compile 'com.google.android.gms:play-services:7.5.0'
compile 'org.java-websocket:Java-WebSocket:1.3.0'
compile 'com.github.nkzawa:engine.io-client:0.6.0'
compile 'com.github.nkzawa:socket.io-client:0.6.0'
compile 'com.github.rey5137:material:1.2.1'
compile files('libs/volley.jar')
compile files('libs/httpclient-4.5.1.jar')
compile files('libs/httpcore-4.5.1.jar')
compile 'com.facebook.android:facebook-android-sdk:4.1.0'
}