Calculate distance when knowing longitude and latitude in java

Maven Dependency 

<dependency>
  <groupId>com.javadocmd</groupId>
  <artifactId>simplelatlng</artifactId>
  <version>RELEASE</version>
</dependency>

Getting Started
SimpleLatLng is written and compiled to Java 6. After you have included the library jar in your project or added it as a dependency in your build tool of choice, you can create a point in latitude and longitude as follows:

LatLng point = new LatLng(33.123123, -127.123123);
The important thing to note is that all latitudes and longitudes are handled in degrees using the convention that positive latitudes are in the northern hemisphere and positive longitudes are east of the Prime Meridian.

This library generally considers degree measurements to the millionth (0.000001) degree. So 33.0000010 is equal to 33.0000015, but not equal to 33.0000020. This yields a resolution of around 1 centimeter which is far more accurate than the distance calculations require.

When a LatLng point is constructed, its latitude and longitude will be normalized to fall within the ±90 degrees latitude, ±180 degree longitude range. Special case: if your LatLng is constructed at a pole (±90 degrees latitude), its longitude will be set to 0 because all longitudes intersect at the poles.
Distance between two points

To calculate the distance between two points, use the static methods in LatLngTool.
LatLng point1 = new LatLng(33.123123, -127.123123);
LatLng point2 = new LatLng(33.321321, -127.321321);
double distanceInMiles = LatLngTool.distance(point1, point2, LengthUnit.MILE);
All supported units of length are contained by the enum LengthUnit. We will add supported units if there is call for them.

Reference 

SimpleLatLng is a Java implementation of common latitude and longitude calculations.

Algorithm to find all Latitude Longitude locations within a certain distance from a given Lat Lng location

Spring Data Elasticsearch

index Latitude and Longitude and fast SQL query