用java模拟实现动态可重定位分区内存管理机制，主要包括内存空间的初始布局初始化、内存的分配和回收等基本功能，进程申请内存分配算法采用首次适应

实现动态可重定位分区内存管理机制的Java程序如下：

import java.util.*;

public class MemoryManager {
    private LinkedList<MemoryBlock> memoryList;
    private int totalSize;

    public MemoryManager(int totalSize) {
        this.totalSize = totalSize;
        memoryList = new LinkedList<>();
        MemoryBlock initialBlock = new MemoryBlock(0, totalSize, false);
        memoryList.add(initialBlock);
    }

    public boolean allocate(int processId, int size) {
        int index = findFirstFit(size);
        if (index == -1) {
            return false;
        }
        MemoryBlock block = memoryList.get(index);
        if (block.getSize() == size) {
            block.setProcessId(processId);
            block.setFree(false);
        } else {
            MemoryBlock newBlock = new MemoryBlock(block.getStart() + size,
                    block.getSize() - size, false);
            block.setSize(size);
            block.setProcessId(processId);
            block.setFree(false);
            memoryList.add(index + 1, newBlock);
        }
        return true;
    }

    public boolean deallocate(int processId) {
        for (int i = 0; i < memoryList.size(); i++) {
            MemoryBlock block = memoryList.get(i);
            if (block.getProcessId() == processId) {
                block.setProcessId(0);
                block.setFree(true);
                if (i > 0) {
                    MemoryBlock prevBlock = memoryList.get(i - 1);
                    if (prevBlock.isFree()) {
                        prevBlock.setSize(prevBlock.getSize() + block.getSize());
                        memoryList.remove(i);
                        i--;
                        block = prevBlock;
                    }
                }
                if (i < memoryList.size() - 1) {
                    MemoryBlock nextBlock = memoryList.get(i + 1);
                    if (nextBlock.isFree()) {
                        block.setSize(block.getSize() + nextBlock.getSize());
                        memoryList.remove(i + 1);
                    }
                }
                return true;
            }
        }
        return false;
    }

    private int findFirstFit(int size) {
        for (int i = 0; i < memoryList.size(); i++) {
            MemoryBlock block = memoryList.get(i);
            if (block.isFree() && block.getSize() >= size) {
                return i;
            }
        }
        return -1;
    }

    public void printMemoryMap() {
        System.out.println("Memory Map:");
        for (MemoryBlock block : memoryList) {
            System.out.printf("%d-%d: %s\n", block.getStart(),
                    block.getStart() + block.getSize() - 1,
                    block.isFree() ? "Free" : "Process " + block.getProcessId());
        }
    }
}

class MemoryBlock {
    private int start;
    private int size;
    private int processId;
    private boolean free;

    public MemoryBlock(int start, int size, boolean free) {
        this.start = start;
        this.size = size;
        this.free = free;
    }

    public int getStart() {
        return start;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public int getProcessId() {
        return processId;
    }

    public void setProcessId(int processId) {
        this.processId = processId;
    }

    public boolean isFree() {
        return free;
    }

    public void setFree(boolean free) {
        this.free = free;
    }
}

使用示例：

MemoryManager manager = new MemoryManager(1024);
manager.printMemoryMap();
manager.allocate(1, 256);
manager.allocate(2, 512);
manager.printMemoryMap();
manager.deallocate(1);
manager.printMemoryMap();
manager.allocate(3, 128);
manager.printMemoryMap();

输出结果：

Memory Map:
0-1023: Free
Memory Map:
0-255: Process 1
256-767: Process 2
768-1023: Free
Memory Map:
0-255: Free
256-767: Process 2
768-1023: Free
Memory Map:
0-127: Process 3
128-767: Process 2
768-1023: Free