FULL PRODUCT VERSION :
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)

A DESCRIPTION OF THE PROBLEM :
Current interface for operating with Properties through System class is vulnerable.
1) All System#getProperties, System#setProperty and System#setProperties are public.
2) Their concurrent usage leads CME to happen.
E.g:
com.sun.corba.se.impl.orb.DataCollectorBase#getSystemPropertyNames
simultaneously with java.util.TimeZone#setDefaultZone
leads to ConcurrentModificationException.

JD contract for class System doesn't reflect that problem. Iterating over properties have to be synchronized.

REGRESSION. Last worked in version 7u75

ADDITIONAL REGRESSION INFORMATION:
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Iterate on System.getProperties() from one thread, and in the same time call System.setProperty() from other thread.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
There is no ConcurrentModificationException.
ACTUAL -
ConcurrentModificationException happens.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
        at java.util.Hashtable$Enumerator.next(Hashtable.java:1167)
        at java.util.AbstractMap.putAll(AbstractMap.java:272)
        at java.util.TreeMap.putAll(TreeMap.java:322)
        at java.util.TreeMap.<init>(TreeMap.java:180)
        at com.devexperts.**** // sys = new TreeMap<String, String>((Map)System.getProperties());


REPRODUCIBILITY :
This bug can be reproduced rarely.

---------- BEGIN SOURCE ----------
Thread1: new TreeMap<String, String>((Map)System.getProperties());
Thread2: System.setProperty("wow", "such_problem");

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
 synchronized (System.getProperties()) {
    sys = new TreeMap<String, String>((Map)System.getProperties());
}