Default values for Xmx, Xms, MaxPermSize on non-server-class machines

Solution 1:

Default values for JDK 1.6.0_29 on Windows 7/32-bit:

-Xmx256m
-XX:MaxPermSize=64m

Also value of these option can be printed by following command:

java -XX:+UnlockExperimentalVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+PrintFlagsFinal -version 2>&1

Then look for MaxHeapSize and MaxPermSize keys and see default values.

uintx InitialHeapSize                          := 199947456       {product}
uintx MaxHeapSize                              := 268435456       {product}           
uintx MaxPermSize                               = 67108864        {pd product}        

Here is the Ultimate HotSpot VM Options Cheat Sheet with defaults and descriptions for last 5 versions of JDK (7, 8, 9, 10 & 11).