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execution failed for tasks: multiple dex files define for appcompat version

android {
compileSdkVersion 27
buildToolsVersion "27.0.3"
defaultConfig {
applicationId "com.example.ceinfo.firebaseproject"
minSdkVersion 15
targetSdkVersion 19
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:27.0.0'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
}
apply plugin: 'com.google.gms.google-services'
When I want to execute espresso test run, it shows me an error of multiple dex files define, I have set my appcompat version to 27.0.0, please suggest me solution to this error.

android showing crunching failed in windows 10

Error showing after adding after converting image to nine patch.
enter image description here
Given code below is my build.gradle (app) code where i added aaptOption and other tag .After that also still showing error.
apply plugin: 'com.android.application'
android {
compileSdkVersion 25
buildToolsVersion "26.0.1"
defaultConfig {
applicationId "com.example.shailajakori.customdialogassignment1"
minSdkVersion 14
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
multiDexEnabled false
}
aaptOptions{
cruncherEnabled=false;
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
dexOptions {
preDexLibraries true
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
compile 'com.android.support:support-v4:25.3.1'
testCompile 'junit:junit:4.12'
}

Android : app running issue on Nougat OS

I am working on an android app. Everything is working fine on marshmallow OS. But when i try to install app on Nougat OS then it is not allow me to install my app.
These is how my gradle file looks like :
apply plugin: 'com.android.application'
android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
applicationId "com.example.*****"
minSdkVersion 19
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.android.support.constraint:constraint-layout:1.0.1'
testCompile 'junit:junit:4.12'
}

Failed to resolve: org.roboelectric:roboelectric:3.2.2

I am learning unit testing for my android apps. I am using roboelectric framework to achieve this.
build.gradle
apply plugin: 'com.android.application'
apply plugin: 'realm-android'
android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
applicationId "com.xyz.helloworld"
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
dataBinding {
enabled = true
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.1.1'
testCompile 'junit:junit:4.12'
testCompile 'org.robolectric:robolectric:3.2.2'
}
I am getting an error Failed to resolve: org.roboelectric:roboelectric:3.2.2 & synced with Gradle multiple times.
How can I resolve this issue? Thanks in advance

It was some proxy kinda issue. I switched to different network then it worked for me. Thanks

Failed to resolve javax

I created a new Application and I am getting these errors
This is my app level
apply plugin: 'com.android.application'
android {
compileSdkVersion 24
buildToolsVersion "24.0.2"
defaultConfig {
applicationId "com.vfirst.genie"
minSdkVersion 15
targetSdkVersion 24
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:24.2.1'
testCompile 'junit:junit:4.12'
}

Download the latest version of Android Support Repository, Android Support Library and Google Repository from your SDK Manager.
I think it should solve the issue.