Archive for April, 2017

remove duplicate from java list

For object comparison  override equal and hashcode

such as

User.java
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
BaseEntity other = (BaseEntity) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}

List updatedMultListWithoutDuplicate = new ArrayList<>(new HashSet<>(duplicatedMultList));

http://www.baeldung.com/java-remove-duplicates-from-list

https://www.dotnetperls.com/duplicates-java

 

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