fix serialization by reversing bytes array because of big endian vs little endian.

.idea/libraries/Maven__commons_lang_commons_lang_2_5.xml

+<component name="libraryTable">
+  <library name="Maven: commons-lang:commons-lang:2.5">
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/commons-lang/commons-lang/2.5/commons-lang-2.5.jar!/" />
+    </CLASSES>
+    <JAVADOC>
+      <root url="jar://$MAVEN_REPOSITORY$/commons-lang/commons-lang/2.5/commons-lang-2.5-javadoc.jar!/" />
+    </JAVADOC>
+    <SOURCES>
+      <root url="jar://$MAVEN_REPOSITORY$/commons-lang/commons-lang/2.5/commons-lang-2.5-sources.jar!/" />
+    </SOURCES>
+  </library>
+</component>
\ No newline at end of file

freud-java-serialization.iml

@@ -18,5 +18,6 @@
     <orderEntry type="library" name="Maven: org.checkerframework:checker-qual:3.5.0" level="project" />
     <orderEntry type="library" name="Maven: com.google.errorprone:error_prone_annotations:2.3.4" level="project" />
     <orderEntry type="library" name="Maven: com.google.j2objc:j2objc-annotations:1.3" level="project" />
+    <orderEntry type="library" name="Maven: commons-lang:commons-lang:2.5" level="project" />
   </component>
 </module>
\ No newline at end of file

pom.xml

@@ -26,6 +26,11 @@
             <artifactId>guava</artifactId>
             <version>30.0-jre</version>
         </dependency>
+        <dependency>
+            <groupId>commons-lang</groupId>
+            <artifactId>commons-lang</artifactId>
+            <version>2.5</version>
+        </dependency>
     </dependencies>
     
 </project>
\ No newline at end of file

src/main/java/Main.java

 import com.google.common.primitives.Ints;
+import org.apache.commons.lang.ArrayUtils;
 
 import java.io.*;
 import java.nio.ByteBuffer;
@@ -12,40 +13,6 @@ public class Main {
         TestClassToSerialize myObject = new TestClassToSerialize();
         fillObject(myObject);
         createBinaryFile(myObject);
-//        readFile();
-    }
-
-    private static void readFile() throws IOException {
-        FileInputStream fis = new FileInputStream(PATHNAME);
-        int i;
-        byte[] bytes;
-        // name_len
-        bytes = new byte[8];
-        i = fis.read(bytes);
-        long nameLen = bytesToLong(bytes);
-        System.out.println("read " + i + " bytes" +
-                " for variable name_len, the content is: " + nameLen);
-        // fname
-        bytes = new byte[(int) nameLen];
-        i = fis.read(bytes);
-        String fName = new String(bytes);
-        System.out.println("read " + i + " bytes" +
-                " for variable fname, the content is: " + fName);
-        // feature_names_count
-        bytes = new byte[8];
-        i = fis.read(bytes);
-        long featureNamesCount = bytesToLong(bytes);
-        System.out.println("read " + i + " bytes" +
-                " for variable feature_names_count" +
-                ", the content is: " + featureNamesCount);
-        fis.close();
-    }
-
-    public static long bytesToLong(byte[] bytes) {
-        ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
-        buffer.put(bytes);
-        buffer.flip();//need flip
-        return buffer.getLong();
     }
 
     private static void createBinaryFile(TestClassToSerialize myObject) throws IOException {
@@ -55,36 +22,16 @@ public class Main {
     }
 
     private static void writeObjectToFile(FileOutputStream fos, TestClassToSerialize myObject) throws IOException {
-        fos.write(longToBytes(myObject.getNameLen()));
-//        fos.write(myObject.getFname().getBytes());
-//        fos.write(longToBytes(myObject.getFeatureNamesCount()));
+        fos.write(intToByteArray(myObject.getNameLen()));
+        fos.write(myObject.getFname().getBytes());
+        fos.write(intToByteArray(myObject.getFeatureNamesCount()));
         fos.close();
     }
 
     public static byte[] intToByteArray(int data) {
-        return Ints.toByteArray(data);
-    }
-//    public static final byte[] intToByteArray(int value) {
-//        return new byte[] {
-//                (byte)(value >>> 24),
-//                (byte)(value >>> 16),
-//                (byte)(value >>> 8),
-//                (byte)value};
-//    }
-
-//    public static byte[] intToByteArray( int data ) {
-//        byte[] result = new byte[4];
-//        result[0] = (byte) ((data & 0xFF000000) >> 24);
-//        result[1] = (byte) ((data & 0x00FF0000) >> 16);
-//        result[2] = (byte) ((data & 0x0000FF00) >> 8);
-//        result[3] = (byte) ((data & 0x000000FF) >> 0);
-//        return result;
-//    }
-
-    public static byte[] longToBytes(long x) {
-        ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
-        buffer.putLong(x);
-        return Arrays.copyOfRange(buffer.array(), 4, 8);
+        byte[] bytes = Ints.toByteArray(data);
+        ArrayUtils.reverse(bytes);
+        return bytes;
     }
 
     private static void fillObject(TestClassToSerialize myObject) {

src/main/java/TestClassToSerialize.java

 import java.io.Serializable;
 
 public class TestClassToSerialize implements Serializable {
-    private long nameLen;
+    private int nameLen;
     private String fname;
 
     // FEATURE NAMES
-    private long featureNamesCount;
+    private int featureNamesCount;
     private long vnlen;
     private String vname;
 
-    public void setNameLen(long nameLen) {
+    public void setNameLen(int nameLen) {
         this.nameLen = nameLen;
     }
 
@@ -17,7 +17,7 @@ public class TestClassToSerialize implements Serializable {
         this.fname = fname;
     }
 
-    public void setFeatureNamesCount(long featureNamesCount) {
+    public void setFeatureNamesCount(int featureNamesCount) {
         this.featureNamesCount = featureNamesCount;
     }
 
@@ -29,7 +29,7 @@ public class TestClassToSerialize implements Serializable {
         this.vname = vname;
     }
 
-    public long getNameLen() {
+    public int getNameLen() {
         return nameLen;
     }
 
@@ -37,7 +37,7 @@ public class TestClassToSerialize implements Serializable {
         return fname;
     }
 
-    public long getFeatureNamesCount() {
+    public int getFeatureNamesCount() {
         return featureNamesCount;
     }