Answer by qmc for What is the default maximum heap size for Sun's JVM from Java SE 6?

java 1.6.0_21 or later, or so...

$ java -XX:+PrintFlagsFinal -version 2>&1 | grep MaxHeapSizeuintx MaxHeapSize                         := 12660904960      {product}

It looks like the min(1G) has been removed.

Or on Windows using findstr

C:\>java -XX:+PrintFlagsFinal -version 2>&1 | findstr MaxHeapSize