id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
20830	Reduce heap size of org.openstreetmap.josm.data.osm.Node by 8 bytes	simon04	simon04	"We can save 8 bytes for each `org.openstreetmap.josm.data.osm.Node` instance by moving the `mappaintCacheIdx` from `OsmPrimitive` to `AbstractPrimitive` due to Java's memory layout alignment.

{{{
BEFORE org.openstreetmap.josm.data.osm.Node object internals:
 OFFSET  SIZE         TYPE DESCRIPTION                               VALUE
      0    16              (object header)                           N/A
     16     8         long AbstractPrimitive.id                      N/A
     24     4          int AbstractPrimitive.version                 N/A
     28     4          int AbstractPrimitive.changesetId             N/A
     32     4          int AbstractPrimitive.timestamp               N/A
     36     2        short AbstractPrimitive.flags                   N/A
     38     2              (alignment/padding gap)                  
     40     8         User AbstractPrimitive.user                    N/A
     48     8     String[] AbstractPrimitive.keys                    N/A
     56     2        short OsmPrimitive.mappaintCacheIdx             N/A
     58     6              (alignment/padding gap)                  
     64     8   StyleCache OsmPrimitive.mappaintStyle                N/A
     72     8      DataSet OsmPrimitive.dataSet                      N/A
     80     8       Object OsmPrimitive.referrers                    N/A
     88     8       double Node.lat                                  N/A
     96     8       double Node.lon                                  N/A
    104     8       double Node.east                                 N/A
    112     8       double Node.north                                N/A
    120     8       Object Node.eastNorthCacheKey                    N/A
Instance size: 128 bytes
Space losses: 8 bytes internal + 0 bytes external = 8 bytes total
}}}


{{{
#!patch
diff --git a/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java b/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
index 591048789..47262617a 100644
--- a/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
+++ b/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
@@ -135,6 +135,12 @@ public abstract class AbstractPrimitive implements IPrimitive {
      */
     protected volatile short flags = FLAG_VISIBLE;   // visible per default
 
+    /**
+     * The mappaint cache index for this primitive.
+     * This field belongs to {@code OsmPrimitive}, but due to Java's memory layout alignment
+     */
+    protected short mappaintCacheIdx;
+
     /*-------------------
      * OTHER PROPERTIES
      *-------------------*/
diff --git a/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java b/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java
index 764e4e1d3..496751f98 100644
--- a/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java
+++ b/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java
@@ -145,7 +145,6 @@ public abstract class OsmPrimitive extends AbstractPrimitive implements Template
      * MAPPAINT
      *--------*/
     private StyleCache mappaintStyle;
-    private short mappaintCacheIdx;
 
     @Override
     public final StyleCache getCachedStyle() {
}}}

{{{
AFTER org.openstreetmap.josm.data.osm.Node object internals:
 OFFSET  SIZE         TYPE DESCRIPTION                               VALUE
      0    16              (object header)                           N/A
     16     8         long AbstractPrimitive.id                      N/A
     24     4          int AbstractPrimitive.version                 N/A
     28     4          int AbstractPrimitive.changesetId             N/A
     32     4          int AbstractPrimitive.timestamp               N/A
     36     2        short AbstractPrimitive.flags                   N/A
     38     2        short AbstractPrimitive.mappaintCacheIdx        N/A
     40     8         User AbstractPrimitive.user                    N/A
     48     8     String[] AbstractPrimitive.keys                    N/A
     56     8   StyleCache OsmPrimitive.mappaintStyle                N/A
     64     8      DataSet OsmPrimitive.dataSet                      N/A
     72     8       Object OsmPrimitive.referrers                    N/A
     80     8       double Node.lat                                  N/A
     88     8       double Node.lon                                  N/A
     96     8       double Node.east                                 N/A
    104     8       double Node.north                                N/A
    112     8       Object Node.eastNorthCacheKey                    N/A
Instance size: 120 bytes
Space losses: 0 bytes internal + 0 bytes external = 0 bytes total
}}}
"	enhancement	closed	normal	21.05	Core		fixed	heap profiling intellij yourkit