BAEL-8497 Update "File to InputStream" article

- Added new tests for data input stream and sequence input stream in JavaXToInputStreamUnitTest
- Added new test resource anothersample.txt

core-java-io/src/test/java/org/baeldung/java/io/JavaXToInputStreamUnitTest.java

@@ -1,10 +1,12 @@
 package org.baeldung.java.io;
 
 import java.io.ByteArrayInputStream;
+import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.SequenceInputStream;
 
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
@@ -74,6 +76,28 @@ public class JavaXToInputStreamUnitTest {
         IOUtils.closeQuietly(targetStream);
     }
 
+    @Test
+    public final void givenUsingPlainJava_whenConvertingFileToDataInputStream_thenCorrect() throws IOException {
+        final File initialFile = new File("src/test/resources/sample.txt");
+        final InputStream targetStream = new DataInputStream(new FileInputStream(initialFile));
+
+        IOUtils.closeQuietly(targetStream);
+    }
+    
+    @Test
+    public final void givenUsingPlainJava_whenConvertingFileToSequenceInputStream_thenCorrect() throws IOException {
+        final File initialFile = new File("src/test/resources/sample.txt");
+        final File anotherFile = new File("src/test/resources/anothersample.txt");
+        final InputStream targetStream = new FileInputStream(initialFile);
+        final InputStream anotherTargetStream = new FileInputStream(anotherFile);
+        
+        InputStream sequenceTargetStream = new SequenceInputStream(targetStream, anotherTargetStream);
+
+        IOUtils.closeQuietly(targetStream);
+        IOUtils.closeQuietly(anotherTargetStream);
+        IOUtils.closeQuietly(sequenceTargetStream);
+    }
+
     @Test
     public final void givenUsingGuava_whenConvertingFileToInputStream_thenCorrect() throws IOException {
         final File initialFile = new File("src/test/resources/sample.txt");

core-java-io/src/test/resources/anothersample.txt

@@ -0,0 +1 @@
+...Continues