diff --git a/core/src/main/scala/com/cloudera/spark/MemoryMonitor.scala b/core/src/main/scala/com/cloudera/spark/MemoryMonitor.scala
index 9a85c11..deb7268 100644
--- a/core/src/main/scala/com/cloudera/spark/MemoryMonitor.scala
+++ b/core/src/main/scala/com/cloudera/spark/MemoryMonitor.scala
@@ -2,21 +2,24 @@
 package com.cloudera.spark
 
 import java.lang.management._
-import java.math.{RoundingMode, MathContext}
+import java.math.{MathContext, RoundingMode}
 import java.text.SimpleDateFormat
 import java.util.Locale
-import java.util.concurrent.atomic.{AtomicInteger, AtomicBoolean, AtomicReference}
 import java.util.concurrent._
-
-import scala.collection.JavaConverters._
+import java.util.concurrent.atomic.{AtomicBoolean, AtomicInteger, AtomicReference}
 
 import com.quantifind.sumac.FieldArgs
-
-import org.apache.spark.{TaskContext, SparkContext}
+import com.typesafe.scalalogging.Logger
 import org.apache.spark.executor.ExecutorPlugin
 import org.apache.spark.memory.SparkMemoryManagerHandle
+import org.apache.spark.{SparkContext, TaskContext}
+
+import scala.collection.JavaConverters._
 
 class MemoryMonitor(val args: MemoryMonitorArgs) {
+
+  private[this] val log = Logger(this.getClass)
+  
   val nettyMemoryHandle = SparkNettyMemoryHandle.get()
   val sparkMemManagerHandle = SparkMemoryManagerHandle.get()
   val memoryBean = ManagementFactory.getMemoryMXBean
@@ -59,8 +62,8 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
   val inShutdown = new AtomicBoolean(false)
 
   def showMetricNames: Unit = {
-    println(s"${nMetrics} Metrics")
-    (0 until nMetrics).foreach { idx => println(names(idx))}
+    log.info(s"${nMetrics} Metrics")
+    (0 until nMetrics).foreach { idx => log.info(names(idx))}
   }
 
   def collectSnapshot: MemorySnapshot = {
@@ -81,41 +84,39 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
   }
 
   def showSnapshot(mem: MemorySnapshot): Unit = {
-    println(s"Mem usage at ${MemoryMonitor.dateFormat.format(mem.time)}")
-    println("===============")
+    log.info(s"Mem usage at ${MemoryMonitor.dateFormat.format(mem.time)}")
+    log.info("===============")
     // TODO headers for each getter?
     (0 until nMetrics).foreach { idx =>
       val v = mem.values(idx)
-      println(names(idx) + "\t:" + MemoryMonitor.bytesToString(v) + "(" + v + ")")
+      log.info(names(idx) + "\t:" + MemoryMonitor.bytesToString(v) + "(" + v + ")")
     }
-    println()
-    println()
+    log.info("")
+    log.info("")
   }
 
   def updateAndMaybeShowPeaks(): Unit = {
     val snapshot = collectSnapshot
-    if (peakMemoryUsage.update(snapshot, peakUpdates, reporting)) {
-      showUpdates(snapshot.time, peakMemoryUsage, peakUpdates)
-    }
+    if (peakMemoryUsage.update(snapshot, peakUpdates, reporting)) showUpdates(snapshot.time, peakMemoryUsage, peakUpdates)
   }
 
   def showUpdates(time: Long, peakMemory: MemoryPeaks, updates: PeakUpdate): Unit = {
-    println(s"Peak Memory updates:${MemoryMonitor.dateFormat.format(time)}")
+    log.info(s"Peak Memory updates:${MemoryMonitor.dateFormat.format(time)}")
     (0 until updates.nUpdates).foreach { updateIdx =>
       val metricIdx = updates.updateIdx(updateIdx)
       val name = names(metricIdx)
       val currentVal = MemoryMonitor.bytesToString(peakMemoryUsage.values(metricIdx))
       val rawDelta = updates.delta(updateIdx)
       val delta = (if (rawDelta > 0) "+" else "-") + MemoryMonitor.bytesToString(rawDelta)
-      println(s"$name\t:\t$currentVal ($delta)")
+      log.info(s"$name\t:\t$currentVal ($delta)")
     }
   }
 
   def showPeaks(time: Long): Unit = {
-    println(s"Peak Memory usage so far ${MemoryMonitor.dateFormat.format(time)}")
+    log.info(s"Peak Memory usage so far ${MemoryMonitor.dateFormat.format(time)}")
     // TODO headers for each getter?
     (0 until nMetrics).foreach { idx =>
-      println(names(idx) + "\t:" + MemoryMonitor.bytesToString(peakMemoryUsage.values(idx)) +
+      log.info(names(idx) + "\t:" + MemoryMonitor.bytesToString(peakMemoryUsage.values(idx)) +
         "\t\t\t\t" + MemoryMonitor.dateFormat.format(peakMemoryUsage.peakTimes(idx)))
     }
   }
@@ -127,7 +128,7 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
   def showLastThreadDump: Unit = {
     val threads = lastThreadDump.get()
     if (threads != null) {
-      println("last thread dump:")
+      log.info("last thread dump:")
       MemoryMonitor.showThreadDump(threads)
     }
   }
@@ -136,14 +137,14 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
     Runtime.getRuntime.addShutdownHook(new Thread(){
       override def run(): Unit = {
         inShutdown.set(true)
-        println()
-        println("IN SHUTDOWN")
-        println("================")
+        log.info("")
+        log.info("IN SHUTDOWN")
+        log.info("================")
         val snapshot = collectSnapshot
         showSnapshot(snapshot)
         peakMemoryUsage.update(snapshot, peakUpdates, reporting)
         showPeaks(snapshot.time)
-        println("Last non-shutdown snapshot:")
+        log.info("Last non-shutdown snapshot:")
         showSnapshot(lastNonShutdownSnapshot.get())
 
         showLastThreadDump
@@ -154,25 +155,25 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
   def beanInfo(): Unit = {
 
     memMgrBeans.foreach { mgr =>
-      println(mgr.getName + " is managing " + mgr.getMemoryPoolNames.mkString(","))
+      log.info(mgr.getName + " is managing " + mgr.getMemoryPoolNames.mkString(","))
     }
 
     poolBeans.foreach { pool =>
-      println(pool.getName())
-      println("============")
-      println(pool.getName() + " is managed by " + pool.getMemoryManagerNames.mkString(","))
+      log.info(pool.getName())
+      log.info("============")
+      log.info(pool.getName() + " is managed by " + pool.getMemoryManagerNames.mkString(","))
       if (pool.isUsageThresholdSupported)
-        println("supports usage threshold")
+        log.info("supports usage threshold")
       if (pool.isCollectionUsageThresholdSupported)
-        println("supports collection usage threshold")
+        log.info("supports collection usage threshold")
       pool.getUsage
-      println()
-      println()
+      log.info("")
+      log.info("")
     }
 
-    println("BUFFER POOLS")
+    log.info("BUFFER POOLS")
     bufferPoolsBeans.foreach { bp =>
-      println(s"${bp.getName}: ${bp.getMemoryUsed} / ${bp.getTotalCapacity}")
+      log.info(s"${bp.getName}: ${bp.getMemoryUsed} / ${bp.getTotalCapacity}")
     }
   }
 }
@@ -180,6 +181,7 @@ class MemoryMonitor(val args: MemoryMonitorArgs) {
 object MemoryMonitor {
 
   val dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS")
+  private[this] val log = Logger(this.getClass)
 
   private var monitor: MemoryMonitor = null
   private var shutdownHookInstalled = false
@@ -222,16 +224,16 @@ object MemoryMonitor {
   def listAllMBeans: Unit = {
     val server = ManagementFactory.getPlatformMBeanServer
     val allBeans = server.queryNames(null, null)
-    println("ALL BEANS")
-    println("=============")
-    allBeans.asScala.map{_.toString}.toArray.sorted.foreach { ob => println(ob) }
-    println()
-    println()
+    log.info("ALL BEANS")
+    log.info("=============")
+    allBeans.asScala.map{_.toString}.toArray.sorted.foreach { ob => log.info(ob) }
+    log.info("")
+    log.info("")
   }
 
   def showLimits: Unit = {
-    println("sun.misc.VM.maxDirectMemory(): " + sun.misc.VM.maxDirectMemory())
-    println("Runtime.getRuntime.maxMemory(): " + Runtime.getRuntime.maxMemory())
+    log.info("sun.misc.VM.maxDirectMemory(): " + sun.misc.VM.maxDirectMemory())
+    log.info("Runtime.getRuntime.maxMemory(): " + Runtime.getRuntime.maxMemory())
   }
 
   def installIfSysProps(): Unit = {
@@ -240,9 +242,9 @@ object MemoryMonitor {
       install(args)
       installShutdownHook()
       args.freq.foreach { freq =>
-        println(s"POLLING memory monitor every $freq millis")
+        log.info(s"POLLING memory monitor every $freq millis")
         monitor.showCurrentMemUsage
-        println("done with initial show")
+        log.info("done with initial show")
         startPolling(args)
       }
     }
@@ -252,7 +254,7 @@ object MemoryMonitor {
     if (!SparkMemoryManagerHandle.isDynamicAllocation(sc)) {
       installOnExecutors(sc)
     } else {
-      println ("********* WARNING ***** not installing on executors because of DA")
+      log.info ("********* WARNING ***** not installing on executors because of DA")
     }
   }
 
@@ -263,7 +265,7 @@ object MemoryMonitor {
     } else {
       numTasks
     }
-    println(s"Running $t tasks to install memory monitor on executors")
+    log.info(s"Running $t tasks to install memory monitor on executors")
     sc.parallelize(1 to t, t).foreach { _ =>
       Thread.sleep(sleep)
       installIfSysProps()
@@ -317,17 +319,19 @@ object MemoryMonitor {
   def showThreadDump(threads: Array[ThreadInfo]): Unit = {
     threads.foreach { t =>
       if (t == null) {
-        println("<null thread>")
+        log.info("<null thread>")
       } else {
-        println(t.getThreadId + " " + t.getThreadName + " " + t.getThreadState)
-        t.getStackTrace.foreach { elem => println("\t" + elem) }
-        println()
+        log.info(t.getThreadId + " " + t.getThreadName + " " + t.getThreadState)
+        t.getStackTrace.foreach { elem => log.info("\t" + elem) }
+        log.info("")
       }
     }
   }
 }
 
 class MemoryMonitorExecutorExtension extends ExecutorPlugin {
+  private[this] val log = Logger(this.getClass)
+
   // the "extension class" api just lets you invoke a constructor.  We really just want to
   // call this static method, so that's good enough.
   MemoryMonitor.installIfSysProps()
@@ -356,7 +360,7 @@ class MemoryMonitorExecutorExtension extends ExecutorPlugin {
         val task = scheduler.scheduleWithFixedDelay(new Runnable {
           override def run(): Unit = {
             val d = MemoryMonitor.dateFormat.format(System.currentTimeMillis())
-            println(s"Polled thread dump @ $d")
+            log.info(s"Polled thread dump @ $d")
             MemoryMonitor.showThreadDump(MemoryMonitor.getThreadInfo)
           }
         }, 0, args.threadDumpFreqMillis, TimeUnit.MILLISECONDS)
@@ -397,6 +401,7 @@ class MemoryMonitorArgs extends FieldArgs {
 }
 
 object MemoryMonitorArgs {
+  private[this] val log = Logger(this.getClass)
   val prefix = "memory.monitor."
   val prefixLen = prefix.length
 
@@ -406,7 +411,7 @@ object MemoryMonitorArgs {
         k.substring(prefixLen) -> v
     })
     if (args.stagesToPoll != null && args.stagesToPoll.nonEmpty) {
-      System.out.println(s"will poll thread dumps for stages ${args.stagesToPoll.mkString(",")}")
+      log.info(s"will poll thread dumps for stages ${args.stagesToPoll.mkString(",")}")
     } else {
       args.stagesToPoll = Array()
     }
diff --git a/core/src/main/scala/org/apache/spark/memory/SparkMemoryManagerHandle.scala b/core/src/main/scala/org/apache/spark/memory/SparkMemoryManagerHandle.scala
index 387d7a8..ecd079e 100644
--- a/core/src/main/scala/org/apache/spark/memory/SparkMemoryManagerHandle.scala
+++ b/core/src/main/scala/org/apache/spark/memory/SparkMemoryManagerHandle.scala
@@ -1,7 +1,6 @@
 package org.apache.spark.memory
 
-import com.cloudera.spark.{Reflector, IncrementBytes, MemoryGetter}
-import org.apache.spark.util.{Utils, ThreadStackTrace}
+import com.cloudera.spark.{IncrementBytes, MemoryGetter, Reflector}
 import org.apache.spark.{SparkContext, SparkEnv}
 
 class SparkMemoryManagerHandle(
diff --git a/core/src/test/resources/log4j.properties b/core/src/test/resources/log4j.properties
new file mode 100644
index 0000000..57c87e7
--- /dev/null
+++ b/core/src/test/resources/log4j.properties
@@ -0,0 +1,35 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Set everything to be logged to the file target/unit-tests.log
+test.appender=file,console
+log4j.rootCategory=INFO, ${test.appender}
+log4j.appender.file=org.apache.log4j.FileAppender
+log4j.appender.file.append=true
+log4j.appender.file.file=target/unit-tests.log
+log4j.appender.file.layout=org.apache.log4j.PatternLayout
+log4j.appender.file.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %t %p %c{1}: %m%n
+# Tests that launch java subprocesses can set the "test.appender" system property to
+# "console" to avoid having the child process's logs overwrite the unit test's
+# log file.
+log4j.appender.console=org.apache.log4j.ConsoleAppender
+log4j.appender.console.Threshold=DEBUG
+log4j.appender.console.ImmediateFlush=true
+log4j.appender.console.target=System.out
+log4j.appender.console.layout=org.apache.log4j.PatternLayout
+log4j.appender.console.layout.ConversionPattern=%t: %m%n
+# Ignore messages below warning level from Jetty, because it's a bit verbose
+log4j.logger.org.spark_project.jetty=WARN
diff --git a/core/src/test/scala/com/cloudera/spark/PeakReportingSuite.scala b/core/src/test/scala/com/cloudera/spark/PeakReportingSuite.scala
index 053da98..7b3245a 100644
--- a/core/src/test/scala/com/cloudera/spark/PeakReportingSuite.scala
+++ b/core/src/test/scala/com/cloudera/spark/PeakReportingSuite.scala
@@ -1,11 +1,17 @@
 // (c) Copyright 2018 Cloudera, Inc. All rights reserved.
 package com.cloudera.spark
 
+import com.typesafe.scalalogging.Logger
 import org.scalatest.FunSuite
 
 class PeakReportingSuite extends FunSuite {
 
+  private[this] val log = Logger(this.getClass)
+
   test("increment bytes") {
+
+    log.info("================== test IncrementBytes.report start.")
+
     // delta over 1e7, and 5% increase
     assert(IncrementBytes.report(1e9.toLong, 1.051e9.toLong))
     // delta over 1e7, but less than 5% increase
@@ -19,5 +25,7 @@ class PeakReportingSuite extends FunSuite {
     // increase from small starting point OK
     assert(IncrementBytes.report(0, 1.001e7.toLong))
 
+    log.info("================== test IncrementBytes.report end.")
+
   }
 }
diff --git a/pom.xml b/pom.xml
index 019475d..57ec029 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,10 +1,9 @@
 <project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+        xmlns="http://maven.apache.org/POM/4.0.0"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
-
   <groupId>com.cloudera</groupId>
   <artifactId>spark-memory-parent_2.11</artifactId>
   <version>0.1.0-SNAPSHOT</version>
@@ -27,6 +26,10 @@
     <PermGen>64m</PermGen>
     <MaxPermGen>512m</MaxPermGen>
     <CodeCacheSize>512m</CodeCacheSize>
+
+    <scala-logging.version>3.9.0</scala-logging.version>
+    <slf4j.version>1.7.25</slf4j.version>
+    <log4j.version>1.2.17</log4j.version>
   </properties>
 
   <dependencies>
@@ -46,7 +49,7 @@
     <dependency>
       <groupId>org.apache.spark</groupId>
       <artifactId>spark-core_2.11</artifactId>
-      <version>2.3.0</version>
+      <version>2.3.2</version>
       <scope>provided</scope>
     </dependency>
 
@@ -56,6 +59,35 @@
       <version>3.0.5</version>
       <scope>test</scope>
     </dependency>
+
+    <!-- scala log -->
+    <dependency>
+      <groupId>com.typesafe.scala-logging</groupId>
+      <artifactId>scala-logging_2.11</artifactId>
+      <version>${scala-logging.version}</version>
+    </dependency>
+
+    <!-- slf4j, log4j -->
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <version>${slf4j.version}</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-log4j12</artifactId>
+      <version>${slf4j.version}</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>log4j</groupId>
+      <artifactId>log4j</artifactId>
+      <version>${log4j.version}</version>
+      <scope>provided</scope>
+    </dependency>
+
+
   </dependencies>
 
 
@@ -89,7 +121,7 @@
               <javacArg>${java.version}</javacArg>
             </javacArgs>
           </configuration>
-	  <executions>
+          <executions>
             <execution>
               <id>scala-compile-first</id>
               <phase>process-resources</phase>
@@ -104,8 +136,8 @@
                 <goal>testCompile</goal>
               </goals>
             </execution>
-	  </executions>
-	</plugin>
+          </executions>
+        </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
@@ -126,21 +158,51 @@
         <artifactId>scala-maven-plugin</artifactId>
       </plugin>
       <plugin>
-	<artifactId>maven-assembly-plugin</artifactId>
-	<configuration>
-	  <descriptorRefs>
-	    <descriptorRef>jar-with-dependencies</descriptorRef>
-	  </descriptorRefs>
-	</configuration>
-	<executions>
-	  <execution>
-	    <id>make-assembly</id>
-	    <phase>package</phase>
-	    <goals>
-	      <goal>single</goal>
-	    </goals>
-	  </execution>
-	</executions>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <configuration>
+          <descriptorRefs>
+            <descriptorRef>jar-with-dependencies</descriptorRef>
+          </descriptorRefs>
+        </configuration>
+        <executions>
+          <execution>
+            <id>make-assembly</id>
+            <phase>package</phase>
+            <goals>
+              <goal>single</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>add-source</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>src/main/scala</source>
+              </sources>
+            </configuration>
+          </execution>
+          <execution>
+            <id>add-test-source</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-test-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>src/test/scala</source>
+              </sources>
+            </configuration>
+          </execution>
+        </executions>
       </plugin>
     </plugins>
   </build>