Collection_In_Java/MapOperation.java at master · Siddhi-Programer/Collection_In_Java · GitHub

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importjava.nio.file.CopyOption;
importjava.util.Collection;
importjava.util.Comparator;
importjava.util.HashMap;
importjava.util.Hashtable;
importjava.util.Iterator;
importjava.util.Map;
importjava.util.Map.Entry;
importjava.util.Set;
importjava.util.TreeMap;

// Auther : Sidheshwari

publicclassMapOperation {
publicstaticvoidmain(String[] args) {
System.out.println("HashMap operations....");

HashMaphm = newHashMap();
hm.put("Siddhi",25);
hm.put("Aadi", 50);
hm.put("Shiva", 30);
hm.put("Dhanush",35);
hm.put("Kiran", 23);
System.out.println(hm);
hm.put("Siddhi", 30);
System.out.println(hm);

System.out.println(hm.remove("Aadi"));
System.out.println(hm);

SetkSet = hm.keySet();
System.out.println(kSet);

Collectionc = hm.values();
System.out.println(c);

SetentrySet = hm.entrySet();

System.out.println(entrySet);

Iteratoritr = entrySet.iterator();

while(itr.hasNext()) {
Map.Entryme = (Entry) itr.next();
System.out.println(me.getKey() + "----" + me.getValue());

if (me.getKey().equals("Siddhi")) {
me.setValue(26);
 }
 }

System.out.println(hm);
TreeMapOperationtmp = newTreeMapOperation();
tmp.treeMapCreation();
tmp.treeMapCreationWithCustomizedSorting();

// Hashtable Creation

HashTableOperationht = newHashTableOperation();
ht.createHashTable();


 }
}

classTreeMapOperation {

publicvoidtreeMapCreation() {
TreeMaptm = newTreeMap();
tm.put(100, "Aaa");
tm.put(101,"AaA");
tm.put(99, "Kiya");

System.out.println("\nNatural Sorting using TreeMap :--->");
System.out.println(tm);

	}

publicvoidtreeMapCreationWithCustomizedSorting() {
TreeMaptm = newTreeMap(newMyComparator());
tm.put(100, "Aaa");
tm.put(101,"AaA");
tm.put(99, "Kiya");

System.out.println("\nCustom Sorting using TreeMap :--->");
System.out.println(tm);

	}

}

classHashTableOperation{

publicvoidcreateHashTable() {
Hashtableht = newHashtable();
ht.put("Ajju", 101);
ht.put("Kiran", 102);
ht.put("Aiya",103);
ht.put("ajinkya", 109);
ht.put("abc", 105);
// java.lang.NullPointerException
// ht.put("abcd", null)
System.out.println("\nHashTable creation ....");
System.out.println(ht);
	}
}

classMyComparatorimplementsComparator{

@Override
publicintcompare(Objecto1, Objecto2) {
Integeri1 = (Integer)o1;
Integeri2 = (Integer)o2;

return -i1.compareTo(i2);
	}

}

classMyComparatorFotHashtableimplementsComparator{

@Override
publicintcompare(Objecto1, Objecto2) {
Strings1 = o1.toString();
Strings2 = o2.toString();

return -s1.compareTo(s2);
	}

}