Fix Grid equals (#78)

* Grid equals

* Upd the CHANGELOG

Author: pomadchin

CHANGELOG.md

@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Fix Grid equals [#78](https://github.com/locationtech/proj4j/pull/78)
+
 ## [1.1.4] - 2021-11-03
 
 ### Fixed

src/main/java/org/locationtech/proj4j/datum/Grid.java

@@ -388,17 +388,17 @@ public boolean equals(Object that) {
         if (that instanceof Grid) {
             Grid g = (Grid) that;
             if (gridName == null && g.gridName != null) return false;
-            if (!gridName.equals(g.gridName)) return false;
+            if (gridName != null && !gridName.equals(g.gridName)) return false;
             if (fileName == null && g.fileName != null) return false;
-            if (!fileName.equals(g.fileName)) return false;
+            if (fileName != null && !fileName.equals(g.fileName)) return false;
             if (format == null && g.format != null) return false;
-            if (!format.equals(g.format)) return false;
+            if (format != null && !format.equals(g.format)) return false;
             if (table == null && g.table != null) return false;
-            if (!table.equals(g.table)) return false;
+            if (table != null && !table.equals(g.table)) return false;
             if (next == null && g.next != null) return false;
-            if (!next.equals(g.next)) return false;
+            if (next != null && !next.equals(g.next)) return false;
             if (child == null && g.child != null) return false;
-            if (!child.equals(g.child)) return false;
+            if (child != null && !child.equals(g.child)) return false;
             return true;
         } else {
             return false;