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Supported data types for Java/Kotlin and C# code

Understand the data types that you can transfer between Java/Kotlin code and C# scripts.
Read time 5 minutesLast updated 2 days ago
When accessing Java/Kotlin code from a C# script in Unity, you can pass certain data types. The following table outlines the data types you can send between Java/Kotlin code and C# script, and the ones that you cannot.

Supported data types

Unsupported data types

  • byte, int, short, long
  • float, double
  • bool
  • char
  • string
  • Arrays of any of these supported types
  • Objects/structs that are serialized/deserialized with JSON

Code examples to transfer data between Java and C# code

The following code examples demonstrate how you can send all the supported data types between Java and C# code. You can save these Java and C# code files anywhere in your Unity project.

Example 1: Transfer basic data types

The following C# script uses 
AndroidJavaClass
to call the Java functions to transfer variable data.
using UnityEngine;public class TransferTypes : MonoBehaviour{    void Start()    {        using (AndroidJavaClass pluginClass = new AndroidJavaClass("com.unity3d.player.JavaTransferTypesExample"))        {            //Receive data from Java functions            Debug.Log($"Received from Java Byte: " + pluginClass.CallStatic<sbyte>("getByte"));            Debug.Log($"Received from Java Short: " + pluginClass.CallStatic<short>("getShort"));            Debug.Log($"Received from Java Int: " + pluginClass.CallStatic<int>("getInt"));            Debug.Log($"Received from Java Long: " + pluginClass.CallStatic<long>("getLong"));            Debug.Log($"Received from Java Float: " + pluginClass.CallStatic<float>("getFloat"));            Debug.Log($"Received from Java Double: " + pluginClass.CallStatic<double>("getDouble"));            Debug.Log($"Received from Java Boolean: " + pluginClass.CallStatic<bool>("getBoolean"));            Debug.Log($"Received from Java Char: " + pluginClass.CallStatic<char>("getChar"));            Debug.Log($"Received from Java String: " + pluginClass.CallStatic<string>("getString"));            //Send data to Java functions            pluginClass.CallStatic("setByte", (sbyte)9);            pluginClass.CallStatic("setShort", (short)87);            pluginClass.CallStatic("setInt", 6);            pluginClass.CallStatic("setLong", (long)5);            pluginClass.CallStatic("setFloat", 4.32f);            pluginClass.CallStatic("setDouble", 9.987);            pluginClass.CallStatic("setBoolean", false);            pluginClass.CallStatic("setChar", 'b');            pluginClass.CallStatic("setString", "This string is sent from C#");        }    }}
The following Java code provides functions that the C# script calls to transfer data.
package com.unity3d.player;public class JavaTransferTypesExample {    // Java functions to send data    public static byte getByte() {        return 12;    }    public static short getShort() {        return 34;    }    public static int getInt() {        return 5;    }    public static long getLong() {        return 6;    }    public static float getFloat() {        return 7.89f;    }    public static double getDouble() {        return 1.123;    }    public static boolean getBoolean() {        return true;    }    public static char getChar() {        return 'a';    }    public static String getString() {        return "This string is sent from Java";    }    //Java functions to receive data    public static void setByte(byte value) {        android.util.Log.i("Example", "Received from C# Byte: " + value);    }    public static void setShort(short value) {        android.util.Log.i("Example", "Received from C# Short: " + value);    }    public static void setInt(int value) {        android.util.Log.i("Example", "Received from C# Int: " + value);    }    public static void setLong(long value) {        android.util.Log.i("Example", "Received from C# Long: " + value);    }    public static void setFloat(float value) {        android.util.Log.i("Example", "Received from C# Float: " + value);    }    public static void setDouble(double value) {        android.util.Log.i("Example", "Received from C# Double: " + value);    }    public static void setBoolean(boolean value) {        android.util.Log.i("Example", "Received from C# Boolean: " + value);    }    public static void setChar(char value) {        android.util.Log.i("Example", "Received from C# Char: " + value);    }    public static void setString(String value) {        android.util.Log.i("Example", "Received from C# String: " + value);    }}

Example 2: Transfer complex data types

The following C# script calls the Java functions to transfer complex data types, such as class/object.
using UnityEngine;using System;public class PassComplexStructure : MonoBehaviour{    [Serializable]    public class DataTypes    {        public int number;        public float floatNumber;        public bool boolValue;        public string phrase;    }        void Start()    {        var example = new DataTypes        {            number = 123,            floatNumber = 4.56f,            boolValue = true,            phrase = "Testing passing an object from C# - successful"        };        using var pluginClass = new AndroidJavaClass("com.unity3d.player.JavaPassObject");        var jsonString = JsonUtility.ToJson(example);        pluginClass.CallStatic("setDataSet", jsonString);        var jsonFromJava = pluginClass.CallStatic<string>("getDataSet");        var receivedData = JsonUtility.FromJson<DataTypes>(jsonFromJava);        Debug.Log($@"C# Deserialized from Java JSON: Number: {receivedData.number}, Float: {receivedData.floatNumber}, Bool: {receivedData.boolValue}, String: {receivedData.phrase}");    }}
The following Java code provides functions that the C# script calls.
package com.unity3d.player;import org.json.JSONException;import org.json.JSONObject;public class JavaPassObject {       public static class DataTypes    {        public int number;        public float floatNumber;        public boolean boolValue;        public String phrase;        public DataTypes(int number, float floatNumber, boolean boolValue, String phrase) {            this.number = number;            this.floatNumber = floatNumber;            this.boolValue = boolValue;            this.phrase = phrase;        }        @Override        public String toString() {            return "Java Deserialized from C# JSON:" +               " Number: " + number +               ", Float: " + floatNumber +               ", Bool: " + boolValue +               ", String: " + phrase;            }    }        public static void setDataSet(String value)    {        try {            var jsonObject = new JSONObject(value);                       int number = (int) jsonObject.getInt("number");            float floatNumber = (float) jsonObject.getDouble("floatNumber");            boolean boolValue = (boolean) jsonObject.getBoolean("boolValue");            String phrase = (String) jsonObject.getString("phrase");            var receivedData = new DataTypes(number, floatNumber, boolValue, phrase);            android.util.Log.i("Test", receivedData.toString());        } catch (JSONException e) {            System.err.println("Error parsing JSON: " + e.getMessage());        }    }    public static String getDataSet() throws JSONException    {        var example = new DataTypes(987, 6.54f, false, "Testing passing an object from Java - successful");               var jsonObject = new JSONObject();        jsonObject.put("number", example.number);        jsonObject.put("floatNumber", example.floatNumber);        jsonObject.put("boolValue", example.boolValue);        jsonObject.put("phrase", example.phrase);        return jsonObject.toString();    }}

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