mostly doc and minor cleanup work

core-java/src/test/java/org/baeldung/java/CoreJavaIoUnitTest.java

@@ -1,14 +1,82 @@
 package org.baeldung.java;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Scanner;
+
+import org.apache.commons.io.FileUtils;
 import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.Charsets;
+import com.google.common.io.Files;
 
 public class CoreJavaIoUnitTest {
+    protected final Logger logger = LoggerFactory.getLogger(getClass());
 
     // tests -
 
     @Test
-    public final void whenIteratingAFile_thenCorrect() {
-        //
+    public final void givenUsingGuava_whenIteratingAFile_thenCorrect() throws IOException {
+        final String path = "G:\\full\\train\\input\\" + "trainDataNegative.csv";
+        // final String path = "G:\\full\\train\\input\\" + "trainDataPositive.csv";
+
+        logMemory();
+        Files.readLines(new File(path), Charsets.UTF_8);
+        logMemory();
+    }
+
+    @Test
+    public final void givenUsingCommonsIo_whenIteratingAFile_thenCorrect() throws IOException {
+        final String path = "G:\\full\\train\\input\\" + "trainDataNegative.csv";
+        // final String path = "G:\\full\\train\\input\\" + "trainDataPositive.csv";
+
+        logMemory();
+        FileUtils.readLines(new File(path));
+        logMemory();
+    }
+
+    @Test
+    public final void whenStreamingThroughAFile_thenCorrect() throws IOException {
+        final String path = "G:\\full\\train\\input\\" + "trainDataNegative.csv";
+        // final String path = "G:\\full\\train\\input\\" + "trainDataPositive.csv";
+
+        logMemory();
+
+        FileInputStream inputStream = null;
+        Scanner sc = null;
+        try {
+            inputStream = new FileInputStream(path);
+            sc = new Scanner(inputStream, "UTF-8");
+            while (sc.hasNextLine()) {
+                final String line = sc.nextLine();
+                // System.out.println(line);
+            }
+            // note that Scanner suppresses exceptions
+            if (sc.ioException() != null) {
+                throw sc.ioException();
+            }
+        } finally {
+            if (inputStream != null) {
+                inputStream.close();
+            }
+            if (sc != null) {
+                sc.close();
+            }
+        }
+
+        logMemory();
+    }
+
+    //
+
+    private final void logMemory() {
+        logger.info("Max Memory: {} Mb", Runtime.getRuntime().maxMemory() / 1048576);
+        logger.info("Total Memory: {} Mb", Runtime.getRuntime().totalMemory() / 1048576);
+        logger.info("Free Memory: {} Mb", Runtime.getRuntime().freeMemory() / 1048576);
     }
 
 }
+//