What is build tool?
A build tool is utility program to automate the process of repetitive tasks like compiling source code and creating files etc. A build tool can be executed from the command line.
Note: Apache Ant, Maven and Gradle are the commonly used building tools in java.
Why build tools are used?
Build tools are used to automate the process of repetitive tasks like source code compilation etc and take this burden away from the developers.
Ant:
Ant refers to the Another Neat Tool. Apache ant is the platform independent build tool for java application. It is basically used for building and deploying the java application but can be used for other repetitive tasks like creating files etc.