JRadio buttons

regarding with radio buttons actions

i just want to ask...

the different terms ("names") of an action that will be implemented when defining an action for a radio button

example code:

Code :

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ActionListener sliceActionListener = new ActionListener() {

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another one:

Code :

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ActionListener crustActionListener = new ActionListener() {

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anothe one:

Code :

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 ChangeListener changeListener = new ChangeListener() {

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what is crust? in radioButton action? what kind of action is that? (english pls)
what is slice? in radioButton action? what kind of action is that? (english pls)

it it a good way of practicing my coding habit? when defining a term?

or is it still ok to define my own term... ?

for example my radioButton is just for selecting. is it fine to define it as

Code :

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selectionAction

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?