Learning Goal: I’m working on a operating systems question and need an explanati

Learning Goal: I’m working on a operating systems question and need an explanation and answer to help me learn.The MemoryMangerFIFO class implements the FIFO page replacements algorithm. You will modify this class so that it implements LRU instead.Modify ONLY the MemoryManagerFIFO class.Only modify code that is enclosed in comments. You need to do the following:1) Declare a variable for the data structure. FIFO uses a queue but LRU will use a stack. I recommend using Java’s ArrayList or LinkedList class for the stack.2) Initialize the data structure in the constructor method.3) Update the handlePageFault method. Just add the page number to your data structure.4) Update the pageAccessed method. This method is currently empty of code because FIFO does not use it. LRU must update its data structure by making sure the accessed page is at the top of the stack. Note that the page being accessed is a resident page and should already be in the data structure.5) Update the evictPage method. This method just identifies the page to evict using the data struc
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