Error:Failed to resolve: junit:junit:4.12

Hi everyone am new to Gradle .I am using studio 2.3. Gradle version 3.3, Android plug-in Version 2.3.0. I have tried alot to resolve this problem but couldn’t find a way out kindly help me to resolve this issue.I have already gone through the relevant issues on this forum.

Start by posting the relevant parts of your build.gradle (s) and specific error messages. Your error description is to short to do anything with.
Generally this should work for a normal java plugin:

apply plugin: 'java'
repositories {
dependencies {
  testCompile 'junit:junit:4.12'