I need to sort my ArrayList according to date which is in Student object… If the date(joining date) is same then i need to sort it according to ID… how to do it?
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I need to sort my ArrayList according to date which is in Student object… If the date(joining date) is same then i need to sort it according to ID… how to do it?
This can be done in two common ways.
The easy way
1) Having the Student provide an implementation of Comparable, which ultimately will defer to the Date. This is a very simple operation, but it is a bit of a hack.
The maintainable way
2) Alternatively,the Collections.sort method takes a Comparator as input – and you can easily write a custom comparator that implements the comparison necessary for sorting, by casting the inputs into Student classes, and directly returning the data comparison.
The second solution is more modular and maintainable, unless comparison by date is s fundamental , central aspect of your application.