Allies were expected to fiercely resist with large Dutch army stationed at Java. To fight against them, 40,000 Japanese solders got onto transport convoy to disembark at Java from three directions. On the way, they encountered Allies' fleet and combated with Imperial Navy's fleet escort force. The battle is called 'Battle of the Java Sea' and 'Battle of Sunda Strait'. Japanese army won both and started to disembark.
After the fierce combats, Japan occupied Batavia (present Jakarta) on March 5th and Dutch army in East Indies unconditionally surrendered on March 9th. Japan finally occupied the resource-rich area of Netherlands East Indies, the ultimate target of Southern Operations.