Scala.tools.ns.interpreter memory leak error

Question

I need to implement DSL (Domain Specific Language) using Scala, and this DSL will be interpreted in the Scala interpreter (scala.tools.nsc.interpreter). The problem is that the memory used by the interpreter continues to increase until an outOfMemory exception is thrown. I cannot reinitialize the interpreter every time I have a DSL string to execute, since the interpreter takes time to load. I cannot just call reset () since I need to track some data in the interpreter runtime.

A memory leak has occurred, even I do the following:

while (true) { interpreter.interpret("println(4 + 5)") } 

After a while I will get:

 Exception in thread "main" java.lang.OutOfMemoryError: Java heap space at ch.epfl.lamp.util.ByteArray.<init>(ByteArray.java:24) at ch.epfl.lamp.fjbg.JCode.<init>(JCode.java:47) at ch.epfl.lamp.fjbg.JExtendedCode.<init>(JExtendedCode.java:113) at ch.epfl.lamp.fjbg.FJBGContext.JCode(FJBGContext.java:122) at ch.epfl.lamp.fjbg.JMethod.<init>(JMethod.java:52) at ch.epfl.lamp.fjbg.FJBGContext.JMethod(FJBGContext.java:87) at ch.epfl.lamp.fjbg.JClass.addNewMethod(JClass.java:246) at scala.tools.nsc.backend.jvm.GenJVM$BytecodeGenerator.genMethod(GenJVM.scala:755) at scala.tools.nsc.backend.jvm.GenJVM$BytecodeGenerator$$anonfun$genClass$7.apply(GenJVM.scala:307) at scala.tools.nsc.backend.jvm.GenJVM$BytecodeGenerator$$anonfun$genClass$7.apply(GenJVM.scala:307) at scala.collection.LinearSeqOptimized$class.foreach(LinearSeqOptimized.scala:59) at scala.collection.immutable.List.foreach(List.scala:45) at scala.tools.nsc.backend.jvm.GenJVM$BytecodeGenerator.genClass(GenJVM.scala:307) at scala.tools.nsc.backend.jvm.GenJVM$JvmPhase$$anonfun$run$4.apply(GenJVM.scala:86) at scala.tools.nsc.backend.jvm.GenJVM$JvmPhase$$anonfun$run$4.apply(GenJVM.scala:86) at scala.collection.mutable.HashMap$$anon$2$$anonfun$foreach$3.apply(HashMap.scala:102) at scala.collection.mutable.HashMap$$anon$2$$anonfun$foreach$3.apply(HashMap.scala:102) at scala.collection.Iterator$class.foreach(Iterator.scala:660) at scala.collection.mutable.HashTable$$anon$1.foreach(HashTable.scala:157) at scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:190) at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:43) at scala.collection.mutable.HashMap$$anon$2.foreach(HashMap.scala:102) at scala.tools.nsc.backend.jvm.GenJVM$JvmPhase.run(GenJVM.scala:86) at scala.tools.nsc.Global$Run.compileSources(Global.scala:953) at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.compileAndSaveRun(IMain.scala:756) at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.compile(IMain.scala:731) at scala.tools.nsc.interpreter.IMain$Request.compile(IMain.scala:873) at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:576) at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:543) at com.ericsson.ims_dsl.IMS_Interpreter$$anonfun$e$1.apply(IMS_Interpreter.scala:50) at com.ericsson.ims_dsl.IMS_Interpreter$$anonfun$e$1.apply(IMS_Interpreter.scala:50) at scala.tools.nsc.interpreter.IMain.beQuietDuring(IMain.scala:200) 

Can someone please help me solve this problem?

Answer 1

Each time you call the interpret method, the request is saved. Therefore, if you try to call an infinite amount of time by this method, you must run into difficulties. So this is not a mistake.

You can increase the number of possible iterations before the crash by increasing the maximum heap size of the JVM ... You can count the number of possible calls to check if it suits your purpose.