If you're getting the following error when opening a large Heap dump file via Eclipse Memory Analyzer (MAT), follow the steps given to solve the issue.

Problem

Error when opening larger Heap dumps.

Reason

Eclipse Memory Analyzer does not have enough heap space to open the Heap dump file.

Solution

1. open the MemoryAnalyzer.ini file

2. change the default -Xmx1024m to a larger size (Ex: Xmx2048m)

Now you’ll be able to open the Heap dump file. 

Hope this helps. Cheers!