Execution Sequence of Gradle Cycle

does the defaultTasks choice override/replace what gradle would normally do or is it in addition to it.

apply plugin: 'war'
defaultTasks 'clean','build','remove', 'copy1',
'copy3', 'makeZip', 'war'

do i need clean and build or will they happen anyway ?

The method defaultTask does not override or replace existing tasks. It merely defines the task(s) that are run if you don’t specify any on the command line by just executing “gradle”.