BAEL-5429 - How to Fix Java Compiler Error: Illegal Character (#9)

core-java-modules/core-java/pom.xml

@@ -59,6 +59,16 @@
             <artifactId>spring-core</artifactId>
             <version>${spring.core.version}</version>
         </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.gdata</groupId>
+            <artifactId>core</artifactId>
+            <version>1.47.1</version>
+        </dependency>
     </dependencies>
 
     <build>

core-java-modules/core-java/src/test/java/com/baeldung/illegalcharacter/IllegalCharacterUnitTest.java

@@ -0,0 +1,79 @@
+package com.baeldung.illegalcharacter;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.Objects;
+
+import org.apache.commons.io.ByteOrderMark;
+import org.apache.commons.io.input.BOMInputStream;
+import org.junit.Test;
+
+import com.google.gdata.util.io.base.UnicodeReader;
+
+public class IllegalCharacterUnitTest {
+
+    final String RESOURCE_FILE_NAME = "bom-file.txt";
+    final InputStream ioStream = this.getClass()
+        .getClassLoader()
+        .getResourceAsStream(RESOURCE_FILE_NAME);
+    final String expected = "Hello world with BOM.";
+
+    @Test
+    public void whenInputFileHasBOM_thenUseInputStream() throws IOException {
+        String line;
+        String actual = "";
+
+        try (BufferedReader br = new BufferedReader(new InputStreamReader(ioStream))) {
+            while ((line = br.readLine()) != null) {
+                actual += line;
+            }
+        }
+
+        assertNotEquals(expected, actual);
+    }
+
+    @Test
+    public void whenInputFileHasBOM_thenUseInputStreamWithReplace() throws IOException {
+        String line;
+        String actual = "";
+
+        try (BufferedReader br = new BufferedReader(new InputStreamReader(Objects.requireNonNull(ioStream)))) {
+            while ((line = br.readLine()) != null) {
+                actual += line.replace("\uFEFF", "");
+            }
+        }
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void whenInputFileHasBOM_thenUseBOMInputStream() throws IOException {
+        String line;
+        String actual = "";
+
+        try (BufferedReader br = new BufferedReader(new InputStreamReader(new BOMInputStream(ioStream, false, ByteOrderMark.UTF_8, ByteOrderMark.UTF_16BE, ByteOrderMark.UTF_16LE, ByteOrderMark.UTF_32BE, ByteOrderMark.UTF_32LE)))) {
+            while ((line = br.readLine()) != null) {
+                actual += line;
+            }
+        }
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void whenInputFileHasBOM_thenUseGoogleGdata() throws IOException {
+        char[] actual = new char[21];
+
+        try (Reader r = new UnicodeReader(ioStream, null)) {
+            r.read(actual);
+        }
+
+        assertEquals(expected, String.valueOf(actual));
+    }
+}

core-java-modules/core-java/src/test/resources/bom-file.txt

@@ -0,0 +1 @@
+Hello world with BOM.