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Java 8 - forEach method example with Map
forEach is a new method introduced in Java 8 to iterate over collections. Here is an example on forEach method
to iterate over Map.
package com.java2novice.java8;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
public class ForEachMapEx {
public static void main(String a[]) {
Map<String, String> countryMap = new HashMap<>();
countryMap.put("India", "Delhi");
countryMap.put("USA", "Washington, D.C.");
countryMap.put("Japan", "Tokyo");
countryMap.put("Canada", "Ottawa");
// iterate through Map normal way
ForEachMapEx.iterateMap(countryMap);
// iterate through Map using forEach method
ForEachMapEx.iterateMapUsingForEach(countryMap);
}
public static void iterateMap(Map<String, String> countryMap) {
System.out.println("<----------Iterating in normal way------------->");
for(Entry<String, String> entry:countryMap.entrySet()) {
System.out.println("Country: "+entry.getKey()+" : Capital: "+entry.getValue());
}
}
public static void iterateMapUsingForEach(Map<String, String> countryMap) {
System.out.println("\n<----------Iterating using forEach method------------>");
countryMap.forEach((k,v)->System.out.println("Country: "+k+" : Capital: "+v));
countryMap.forEach((k,v)->{
// you can implement some business logic here..
});
}
}
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| Output: |
<----------Iterating in normal way------------->
Country: Canada : Capital: Ottawa
Country: USA : Capital: Washington, D.C.
Country: Japan : Capital: Tokyo
Country: India : Capital: Delhi
<----------Iterating using forEach method------------>
Country: Canada : Capital: Ottawa
Country: USA : Capital: Washington, D.C.
Country: Japan : Capital: Tokyo
Country: India : Capital: Delhi
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Java 8 forEach method examples
- Java 8 forEach example with Map
- Java 8 forEach example with List
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wait Vs sleep methods
sleep():
It is a static method on Thread class. It makes the current thread into the
"Not Runnable" state for specified amount of time. During this time, the thread
keeps the lock (monitors) it has acquired.
wait():
It is a method on Object class. It makes the current thread into the "Not Runnable"
state. Wait is called on a object, not a thread. Before calling wait() method, the
object should be synchronized, means the object should be inside synchronized block.
The call to wait() releases the acquired lock.
Good judgment comes from experience, and experience comes from bad judgment.
-- Barry LePatner
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