We can use memory management related methods provided in java.lang.Runtime class to get the free memory, total memory and maximum heap memory in Java.

By using these methods, you can find out how much of the heap is used and how much heap space still remains.

• Runtime.freeMemory() returns amount of free memory in bytes.
• Runtime.totalMemory() returns total memory in bytes.
• Runtime.maxMemory() returns maximum memory in bytes.