diff --git a/core-java/src/main/java/com/baeldung/nestedclass/Enclosing.java b/core-java/src/main/java/com/baeldung/nestedclass/Enclosing.java
deleted file mode 100644
index a9911538b0..0000000000
--- a/core-java/src/main/java/com/baeldung/nestedclass/Enclosing.java
+++ /dev/null
@@ -1,11 +0,0 @@
-package com.baeldung.nestedclass;
-
-public class Enclosing {
-
-    public static class Nested {
-
-        public void test() {
-            System.out.println("Calling test...");
-        }
-    }
-}
diff --git a/core-java/src/main/java/com/baeldung/nestedclass/NewEnclosing.java b/core-java/src/main/java/com/baeldung/nestedclass/NewEnclosing.java
deleted file mode 100644
index c7e04e8600..0000000000
--- a/core-java/src/main/java/com/baeldung/nestedclass/NewEnclosing.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package com.baeldung.nestedclass;
-
-public class NewEnclosing {
-
-    void run() {
-        class Local {
-
-            void run() {
-                System.out.println("Welcome to Baeldung!");
-            }
-        }
-        Local local = new Local();
-        local.run();
-    }
-}
\ No newline at end of file
diff --git a/core-java/src/main/java/com/baeldung/nestedclass/Outer.java b/core-java/src/main/java/com/baeldung/nestedclass/Outer.java
deleted file mode 100644
index ebd6d27293..0000000000
--- a/core-java/src/main/java/com/baeldung/nestedclass/Outer.java
+++ /dev/null
@@ -1,11 +0,0 @@
-package com.baeldung.nestedclass;
-
-public class Outer {
-
-    public class Inner {
-
-        public void test() {
-            System.out.println("Calling test...");
-        }
-    }
-}
diff --git a/core-java/src/main/java/com/baeldung/nestedclass/SimpleAbstractClass.java b/core-java/src/main/java/com/baeldung/nestedclass/SimpleAbstractClass.java
deleted file mode 100644
index 586e2d12b4..0000000000
--- a/core-java/src/main/java/com/baeldung/nestedclass/SimpleAbstractClass.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.baeldung.nestedclass;
-
-abstract class SimpleAbstractClass {
-    abstract void run();
-}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java b/core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java
deleted file mode 100644
index 451c1b4c4d..0000000000
--- a/core-java/src/test/java/com/baeldung/file/FileOutputStreamTest.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package com.baeldung.file;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.PrintWriter;
-
-import org.junit.After;
-import org.junit.Test;
-
-import com.baeldung.util.StreamUtils;
-
-public class FileOutputStreamTest {
-
-    public static final String fileName = "src/main/resources/countries.properties";
-
-    @Test
-    public void whenAppendToFileUsingFileOutputStream_thenCorrect() throws Exception {
-        FileOutputStream fos = new FileOutputStream(fileName, true);
-        fos.write("Spain\r\n".getBytes());
-        fos.close();
-
-        assertThat(StreamUtils.getStringFromInputStream(
-          new FileInputStream(fileName)))
-          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\r\n");
-    }
-
-    @After
-    public void revertFile() throws IOException {
-        PrintWriter writer = new PrintWriter(fileName);
-        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
-        writer.close();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/file/FileUtilsTest.java b/core-java/src/test/java/com/baeldung/file/FileUtilsTest.java
deleted file mode 100644
index 9ee8726575..0000000000
--- a/core-java/src/test/java/com/baeldung/file/FileUtilsTest.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.baeldung.file;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.PrintWriter;
-import java.nio.charset.StandardCharsets;
-
-import org.apache.commons.io.FileUtils;
-import org.junit.After;
-import org.junit.Test;
-
-import com.baeldung.util.StreamUtils;
-
-public class FileUtilsTest {
-
-    public static final String fileName = "src/main/resources/countries.properties";
-
-    @Test
-    public void whenAppendToFileUsingFiles_thenCorrect() throws IOException {
-        File file = new File(fileName);
-        FileUtils.writeStringToFile(file, "Spain\r\n", StandardCharsets.UTF_8, true);
-        
-        assertThat(StreamUtils.getStringFromInputStream(
-          new FileInputStream(fileName)))
-          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\r\n");
-    }
-    
-    @After
-    public void revertFile() throws IOException {
-        PrintWriter writer = new PrintWriter(fileName);
-        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
-        writer.close();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/file/FileWriterTest.java b/core-java/src/test/java/com/baeldung/file/FileWriterTest.java
deleted file mode 100644
index 8d2ce4310e..0000000000
--- a/core-java/src/test/java/com/baeldung/file/FileWriterTest.java
+++ /dev/null
@@ -1,40 +0,0 @@
-package com.baeldung.file;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.io.BufferedWriter;
-import java.io.FileInputStream;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.io.PrintWriter;
-
-import org.junit.After;
-import org.junit.Test;
-
-import com.baeldung.util.StreamUtils;
-
-public class FileWriterTest {
-    
-    public static final String fileName = "src/main/resources/countries.properties";
-
-    @Test
-    public void whenAppendToFileUsingFileWriter_thenCorrect() throws IOException {
-        FileWriter fw = new FileWriter(fileName, true);
-        BufferedWriter bw = new BufferedWriter(fw);
-        bw.write("Spain");
-        bw.newLine();
-        bw.close();
-
-        assertThat(
-          StreamUtils.getStringFromInputStream(
-          new FileInputStream(fileName)))
-          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\n");
-    }
-
-    @After
-    public void revertFile() throws IOException {
-        PrintWriter writer = new PrintWriter(fileName);
-        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
-        writer.close();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/file/GuavaTest.java b/core-java/src/test/java/com/baeldung/file/GuavaTest.java
deleted file mode 100644
index 5a7ec6c4a8..0000000000
--- a/core-java/src/test/java/com/baeldung/file/GuavaTest.java
+++ /dev/null
@@ -1,48 +0,0 @@
-package com.baeldung.file;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.PrintWriter;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
-import com.baeldung.util.StreamUtils;
-import com.google.common.base.Charsets;
-import com.google.common.io.CharSink;
-import com.google.common.io.FileWriteMode;
-import com.google.common.io.Files;
-
-public class GuavaTest {
-
-    public static final String fileName = "src/main/resources/countries.properties";
-    
-    @Before
-    public void setup() throws Exception {
-        PrintWriter writer = new PrintWriter(fileName);
-        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
-        writer.close();
-    }
-
-    @Test
-    public void whenAppendToFileUsingGuava_thenCorrect() throws IOException {
-        File file = new File(fileName);
-        CharSink chs = Files.asCharSink(file, Charsets.UTF_8, FileWriteMode.APPEND);
-        chs.write("Spain\r\n");
-        
-        assertThat(StreamUtils.getStringFromInputStream(
-          new FileInputStream(fileName)))
-          .isEqualTo("UK\r\n" + "US\r\n" + "Germany\r\n" + "Spain\r\n");
-    }
-    
-    @After
-    public void revertFile() throws IOException {
-        PrintWriter writer = new PrintWriter(fileName);
-        writer.print("UK\r\n" + "US\r\n" + "Germany\r\n");
-        writer.close();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/nestedclass/AnonymousInnerTest.java b/core-java/src/test/java/com/baeldung/nestedclass/AnonymousInnerTest.java
deleted file mode 100644
index 394c0bb57a..0000000000
--- a/core-java/src/test/java/com/baeldung/nestedclass/AnonymousInnerTest.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package com.baeldung.nestedclass;
-
-import org.junit.Test;
-
-public class AnonymousInnerTest {
-
-    @Test
-    public void whenRunAnonymousClass_thenCorrect() {
-        SimpleAbstractClass simpleAbstractClass = new SimpleAbstractClass() {
-            void run() {
-                System.out.println("Running Anonymous Class...");
-            }
-        };
-        simpleAbstractClass.run();
-    }
-}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/nestedclass/InnerClassTest.java b/core-java/src/test/java/com/baeldung/nestedclass/InnerClassTest.java
deleted file mode 100644
index e9cb119ac2..0000000000
--- a/core-java/src/test/java/com/baeldung/nestedclass/InnerClassTest.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package com.baeldung.nestedclass;
-
-import org.junit.Test;
-
-public class InnerClassTest {
-
-    @Test
-    public void givenInnerClassWhenInstantiating_thenCorrect() {
-        Outer outer = new Outer();
-        Outer.Inner inner = outer.new Inner();
-        inner.test();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/nestedclass/LocalClassTest.java b/core-java/src/test/java/com/baeldung/nestedclass/LocalClassTest.java
deleted file mode 100644
index dad19161ad..0000000000
--- a/core-java/src/test/java/com/baeldung/nestedclass/LocalClassTest.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package com.baeldung.nestedclass;
-
-import org.junit.Test;
-
-public class LocalClassTest {
-
-    @Test
-    public void whenTestingLocalClass_thenCorrect() {
-        NewEnclosing newEnclosing = new NewEnclosing();
-        newEnclosing.run();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/nestedclass/NestedClassTest.java b/core-java/src/test/java/com/baeldung/nestedclass/NestedClassTest.java
deleted file mode 100644
index 16c883689a..0000000000
--- a/core-java/src/test/java/com/baeldung/nestedclass/NestedClassTest.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package com.baeldung.nestedclass;
-
-import org.junit.Test;
-
-public class NestedClassTest {
-
-    @Test
-    public void whenInstantiatingStaticNestedClass_thenCorrect() {
-        Enclosing.Nested nested = new Enclosing.Nested();
-        nested.test();
-    }
-}
diff --git a/core-java/src/test/java/com/baeldung/nestedclass/NewOuterTest.java b/core-java/src/test/java/com/baeldung/nestedclass/NewOuterTest.java
deleted file mode 100644
index e883687d33..0000000000
--- a/core-java/src/test/java/com/baeldung/nestedclass/NewOuterTest.java
+++ /dev/null
@@ -1,32 +0,0 @@
-package com.baeldung.nestedclass;
-
-import static org.junit.Assert.assertEquals;
-import org.junit.Test;
-
-public class NewOuterTest {
-
-    int a = 1;
-    static int b = 2;
-
-    public class InnerClass {
-        int a = 3;
-        static final int b = 4;
-
-        @Test
-        public void whenShadowing_thenCorrect() {
-            assertEquals(3, a);
-            assertEquals(4, b);
-            assertEquals(1, NewOuterTest.this.a);
-            assertEquals(2, NewOuterTest.b);
-            assertEquals(2, NewOuterTest.this.b);
-        }
-    }
-
-    @Test
-    public void shadowingTest() {
-        NewOuterTest outer = new NewOuterTest();
-        NewOuterTest.InnerClass inner = outer.new InnerClass();
-        inner.whenShadowing_thenCorrect();
-
-    }
-}
\ No newline at end of file