diff --git a/Src/PCompiler/CompilerCore/Backend/Java/Constants.cs b/Src/PCompiler/CompilerCore/Backend/Java/Constants.cs
index b21d20ad1..636487481 100644
--- a/Src/PCompiler/CompilerCore/Backend/Java/Constants.cs
+++ b/Src/PCompiler/CompilerCore/Backend/Java/Constants.cs
@@ -26,6 +26,7 @@ internal static class Constants
 
         private static readonly string[] JreDefaultImports =
         {
+            "java.io.Serializable"
             "java.util.*",
         };
 
diff --git a/Src/PCompiler/CompilerCore/Backend/Java/MachineGenerator.cs b/Src/PCompiler/CompilerCore/Backend/Java/MachineGenerator.cs
index b05a576a2..f44072f89 100644
--- a/Src/PCompiler/CompilerCore/Backend/Java/MachineGenerator.cs
+++ b/Src/PCompiler/CompilerCore/Backend/Java/MachineGenerator.cs
@@ -116,7 +116,7 @@ private void WriteMonitorDecl()
 
         private void WriteSupplierCDef(string cname)
         {
-            WriteLine($"public static class Supplier implements java.util.function.Supplier<{cname}> {{");
+            WriteLine($"public static class Supplier implements java.util.function.Supplier<{cname}>, Serializable {{");
             WriteLine($"public {cname} get() {{");
             WriteLine($"{cname} ret = new {cname}();");
             WriteLine("ret.ready();"); // TODO: at this point, we may as well ready() within the monitor's constructor?