Table of Contents

What is the Java hashCode Method?

About

The Java hashCode method outputs a hash creating an unique identifier for the object.

If two objects are equal, they must have the same hashCode() output.

The hashCode is generally overwritten by the developer to be an output of the natural identifier.

When the hashCode method is implemented, the equal method is also implemented to enable the equality of objects.

Example

@Override
public int hashCode() {
   return Objects.hash(firstId, secondId);
}
Java
Download

Utility

org.apache.commons.lang.builder

package org.apache.commons.lang.builder;
HashCodeBuilder builder = new HashCodeBuilder(17, 37);

builder.append(name);
if (table!=null){
	//TODO: May be implementation of an URI for each database object
	builder.append(table.getName());
	builder.append(table.getSchemaObject().getName());
	builder.append(table.getSchemaObject().getCatalog().getName());
	builder.append(table.getSchemaObject().getCatalog().getPlatform().getName());
}


return builder.toHashCode();
Java
Download