Here is a script to compare two jmap class histogram dumps, to see which classes are increasing memory. This can be used as a rough tool in checking suspect classes while analyzing Java memory leaks, as dumping large heaps and analyzing the same can be hard

histogramparser.py

__author__ = 'acp'

import re
import fileinput
import operator
import sys

objectschanged={}

def create_object_list(line2,mapofObjects,instance):
    container = line2.split()
    #print(container)
    if container[3] in mapofObjects:
        val=mapofObjects[container[3]]
        #print(container[3],"difference=",abs(int(container[2])-val))
        objectschanged[container[3]]=(int(container[instance])-val)
    else:
        mapofObjects[container[3]]=int(container[instance])


#Call the main function

print("A Python Script to parse the Jmap generated Histograms ")
print("Author - Alex.Punnen")
print("Usage- jmaphistoparser.py  filename1 filename2")
#print ("Where M is the difference in memory and I difference in isntance and fo")

instance=1 #for instance difference
#instance=2 #for memeory difference

mapofObjects={}
content=[]
for line in fileinput.input():
    content.append(line)

count=0
#skip lines
while len(content) >0 :
    line=content.pop()
    if(':' in  line):
        count+=1
        create_object_list(line,mapofObjects,instance)

print("------------------------Objects Changed Between Heaps-------------------------------------------")
sorted_x = sorted(objectschanged.items(), key=operator.itemgetter(1))
for(x,y) in sorted_x:
   print(x,y)

Good idea.
I have added few more features to this one and reimplemented.
https://github.com/Rachangouda/utils

good that someone finds it useful.

+1
thanks for sharing