Fix code review comments

Author: shivaram

pkg/R/sparkRClient.R

@@ -47,22 +47,22 @@ launchBackendSparkSubmit <- function(
     sparkHome,
     sparkSubmitOpts) {
   if (.Platform$OS.type == "unix") {
-    spark_submit_bin_name = "spark-submit"
+    sparkSubmitBinName = "spark-submit"
   } else {
-    spark_submit_bin_name = "spark-submit.cmd"
+    sparkSubmitBinName = "spark-submit.cmd"
   }
 
   if (sparkHome != "") {
-    spark_submit_bin <- file.path(sparkHome, "bin", spark_submit_bin_name)
+    sparkSubmitBin <- file.path(sparkHome, "bin", sparkSubmitBinName)
   } else {
-    spark_submit_bin <- spark_submit_bin_name
+    sparkSubmitBin <- sparkSubmitBinName
   }
 
   # Since this function is only used while launching R shell using spark-submit,
   # the format we need to construct is
   # spark-submit --class <mainClass> <sparkSubmitOpts> <jarFile> <appOpts>
 
   combinedArgs <- paste("--class", mainClass, sparkSubmitOpts, appJar, args, sep = " ")
-  cat("Launching java with spark-submit command ", spark_submit_bin, " ", combinedArgs, "\n")
-  invisible(system2(spark_submit_bin, combinedArgs, wait = F))
+  cat("Launching java with spark-submit command ", sparkSubmitBin, " ", combinedArgs, "\n")
+  invisible(system2(sparkSubmitBin, combinedArgs, wait = F))
 }

pkg/src/src/main/scala/edu/berkeley/cs/amplab/sparkr/SparkRRunner.scala

@@ -37,8 +37,7 @@ object SparkRRunner {
     // Java system properties etc.
     val sparkRBackend = new SparkRBackend()
     val sparkRBackendThread = new Thread() {
-      val finishedInit = new Semaphore(1)
-      finishedInit.acquire()
+      val finishedInit = new Semaphore(0)
 
       override def run() {
         sparkRBackend.init(sparkRBackendPort)
@@ -58,7 +57,7 @@ object SparkRRunner {
     // Launch R
     val builder = new ProcessBuilder(Seq(rCommand, rFileNormalized) ++ otherArgs)
     val env = builder.environment()
-    env.put("EXISTING_SPARKR_BACKEND_PORT", "" + sparkRBackendPort)
+    env.put("EXISTING_SPARKR_BACKEND_PORT", sparkRBackendPort.toString)
     builder.redirectErrorStream(true) // Ugly but needed for stdout and stderr to synchronize
     val process = builder.start()