Which JVM option sets the initial heap size?

Which JVM option sets the initial heap size?

• A. -Xms
• B. -Xmx
• C. -Xmn
• D. -XX:NewRatio

Answer: (A)

The starting point for memory the JVM allocates to the heap is controlled by the option that sets the initial heap size. The best choice is the one that defines that initial amount, -Xms. For example, -Xms256m starts the JVM with a 256 MB heap. The heap can then grow as needed up to the maximum set by -Xmx, which defines the upper limit for heap growth. If -Xmx isn’t specified, the JVM picks a reasonable default. The other options adjust different aspects: -Xmx sets the maximum heap size; -Xmn specifies the size of the young generation; and -XX:NewRatio controls the ratio between the young and old generations.

The starting point for memory the JVM allocates to the heap is controlled by the option that sets the initial heap size. The best choice is the one that defines that initial amount, -Xms. For example, -Xms256m starts the JVM with a 256 MB heap. The heap can then grow as needed up to the maximum set by -Xmx, which defines the upper limit for heap growth. If -Xmx isn’t specified, the JVM picks a reasonable default. The other options adjust different aspects: -Xmx sets the maximum heap size; -Xmn specifies the size of the young generation; and -XX:NewRatio controls the ratio between the young and old generations.