What does the build task added by the Java plugin do?

Also, which task is added by wrapper plugin to the project?

The wrapper plugin is currently incubating. Please be aware that the DSL and other configuration may change in later Gradle versions. The Gradle wrapper plugin allows the generation of Gradle wrapper files by adding a Wrapper task, that generates all files needed to run the build using the Gradle Wrapper.

Additionally, what happens when we build a Java project? Downloading project dependency JARs, if necessary. Building other dependent projects, if any. Compiling this project's Java source files to classes in a matching folder structure inside the build/target folder. Converting JSPs to Java servlets and compiling them.

In this manner, which is the Java plugin that adds some tasks to your project which will compile and unit test your Java source code and bundle it into a jar file?

Gradle - Build a JAVA Project. This chapter explains about how to build a java project using Gradle build file. First of all we have to add java plugin to the build script because it provides tasks to compile Java source code, run unit tests, create Javadoc and create a JAR file.

Can Gradle tasks can also be created and extended dynamically at runtime?

Gradle tasks can also be created and extended dynamically at run time ,this statement is true is if the task is needed to be executed and the statement is false if the task is not needed to be executed. A separate project can be created by a task class. There are various gradle properties like extras and extensions.