Cracking Core Java Interviews 3rd Edition

A Comprehensive Guide to Crack Core Java Interviews in Investment Banks, HealthCare IT & Startups. It covers Core Java, Algorithms, Data Structures, Concurrency, Hibernate and Spring MVC.

Specifically for investment banking domain, healthcare IT and product companies i.e. UBS, RBS, Blackrock, Morgan Stanley, JP Morgan, Nomura, Barclays, Citibank, Markit, Bank of America, Goldman Sachs and other companies i.e. Global Logic, Adobe, hCentive, Edifecs, Expedia, Infosys, TCS, Sapient, Wipro, HCL etc.
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3rd Edition
Last Updated : Friday, December 4, 2015 1:39:41 PM IST Total Page Hits 479

Write code to remove entries from hashmap while iterating over it?

Iterator’s remove method should be used if you want to remove a map entry while iterating over a map. Please also note that must have been invoked before you actually make a call to iterator.remove().

Iterator<Map.Entry<String,String>> iter = TestMap.entrySet().iterator();
while (iter.hasNext()) {
    Map.Entry<String,String> entry =;

Add entry while iteration

Map<String,String> values = ...

Map<String,String> temp = new HashMap<>();
for (Entry<String,String> entry : values.entrySet()) {
    if ("some value".equals(entry.getValue()) {
        temp.put(entry.getValue(), "another value");

Java 8 Way

map.entrySet().removeIf(e-> <boolean expression> );

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