This course is designed to help you learn Java by doing. Each lab is a small Java project with detailed guidance and solutions. You will practice coding with real-world projects and improve your Java skills.
LabEx is an interactive, hands-on learning platform dedicated to coding and technology. It combines labs, AI assistance, and virtual machines to provide a no-video, practical learning experience.
- A strict “Learn by Doing” approach with exclusive hands-on labs and no videos.
- Interactive online environments within the browser, with automated step-by-step checks.
- A structured content organization with the Skill Tree based learning system.
- A growing learning resource of 30 Skill Trees and over 6,000 Labs.
- The AI learning assistant Labby, built on ChatGPT, providing a conversational learning experience.
Learn more about LabEx VM.
| Index | Name | Difficulty | Practice |
|---|---|---|---|
| 001 | 📖 Introduction to Java Programming | ★☆☆ | Start Lab |
| 002 | 📖 Variables and Operators in Java | ★☆☆ | Start Lab |
| 003 | 📖 Java Conditional Expressions Fundamentals | ★☆☆ | Start Lab |
| 004 | 📖 Recursion and Loops | ★☆☆ | Start Lab |
| 005 | 📖 Methods & Parameters and Object | ★☆☆ | Start Lab |
| 006 | 📖 Number, String and Array | ★☆☆ | Start Lab |
| 007 | 📖 Class and Object | ★☆☆ | Start Lab |
| 008 | 📖 Access Modifiers and Inheritance | ★☆☆ | Start Lab |
| 009 | 📖 Overloading and Overriding | ★☆☆ | Start Lab |
| 010 | 📖 Abstraction and Interface | ★☆☆ | Start Lab |
| 011 | 📖 Polymorphism and Encapsulation | ★☆☆ | Start Lab |
| 012 | 📖 Arranging Classes by Functionality | ★☆☆ | Start Lab |
| 013 | 📖 Java Localdate Parse with Formatter | ★☆☆ | Start Lab |
| 014 | 📖 Java LocalDate getMonth Method | ★☆☆ | Start Lab |
| 015 | 📖 Java LocalDate atTime Method | ★☆☆ | Start Lab |
| 016 | 📖 Java LocalDate isAfter Method | ★☆☆ | Start Lab |
| 017 | 📖 Java LocalDate minusYears Method | ★☆☆ | Start Lab |
| 018 | 📖 Java LocalDate Current Date | ★☆☆ | Start Lab |
| 019 | 📖 Java LocalDate of Method | ★☆☆ | Start Lab |
| 020 | 📖 Java LocalDate Plus Method | ★☆☆ | Start Lab |
| 021 | 📖 Java LocalDate plusMonths Method | ★☆☆ | Start Lab |
| 022 | 📖 Java LocalDate Range Method | ★☆☆ | Start Lab |
| 023 | 📖 Java LocalDate GetDayOfMonth Method | ★☆☆ | Start Lab |
| 024 | 📖 Java LocalDate getMonthValue Method | ★☆☆ | Start Lab |
| 025 | 📖 Calculating Date Periods with Java | ★☆☆ | Start Lab |
| 026 | 📖 Using LocalDate Until Method | ★☆☆ | Start Lab |
| 027 | 📖 Java LocalDate atStartOfDay Method with Time Zone | ★☆☆ | Start Lab |
| 028 | 📖 Java LocalDate Minus Method | ★☆☆ | Start Lab |
| 029 | 📖 Java LocalDate withYear Method | ★☆☆ | Start Lab |
| 030 | 📖 Java Float doubleValue Method | ★☆☆ | Start Lab |
| 031 | 📖 Java LocalDate lengthOfYear Method | ★☆☆ | Start Lab |
| 032 | 📖 Adding Large Integers | ★☆☆ | Start Lab |
| 033 | 📖 Using Java LocalDate Now Clock | ★☆☆ | Start Lab |
| 034 | 📖 Java LocalDate MinusMonth Method | ★☆☆ | Start Lab |
| 035 | 📖 Java Timer and TimerTask | ★☆☆ | Start Lab |
| 036 | 📖 Java Long floatValue Method | ★☆☆ | Start Lab |
| 037 | 📖 Java Long longValue Method | ★☆☆ | Start Lab |
| 038 | 📖 Java LocalDate plusYears Method | ★☆☆ | Start Lab |
| 039 | 📖 Java Integer Compare Method | ★☆☆ | Start Lab |
| 040 | 📖 Java LocalDate Format Method | ★☆☆ | Start Lab |
| 041 | 📖 Java LocalDate GetChronology Method | ★☆☆ | Start Lab |
| 042 | 📖 Java Float Max Method | ★☆☆ | Start Lab |
| 043 | 📖 Java LocalDate isSupported Method | ★☆☆ | Start Lab |
| 044 | 📖 Java Ternary Operator | ★☆☆ | Start Lab |
| 045 | 📖 Convert Array to ArrayList | ★☆☆ | Start Lab |
| 046 | 📖 Java LocalDate plusWeeks Method | ★☆☆ | Start Lab |
| 047 | 📖 Java Integer toBinaryString Method | ★☆☆ | Start Lab |
| 048 | 📖 Java Double longValue Method | ★☆☆ | Start Lab |
| 049 | 📖 Java Integer Numberofleadingzeros Method | ★☆☆ | Start Lab |
| 050 | 📖 Java LocalDate isLeapYear Method | ★☆☆ | Start Lab |
| 051 | 📖 Writing Data Into CSV File Using Java | ★☆☆ | Start Lab |
| 052 | 📖 Java String Split | ★☆☆ | Start Lab |
| 053 | 📖 How to Convert String to Date | ★☆☆ | Start Lab |
| 054 | 📖 Convert Array to Set | ★☆☆ | Start Lab |
| 055 | 📖 Exploring Java Long Hashcode Implementation | ★☆☆ | Start Lab |
| 056 | 📖 Java DoubleToRawLongBits Method | ★☆☆ | Start Lab |
| 057 | 📖 Resolving 'Could Not Find or Load Main Class' Erro... | ★☆☆ | Start Lab |
| 058 | 📖 How to Return an Array | ★☆☆ | Start Lab |
| 059 | 📖 Convert Float to String | ★☆☆ | Start Lab |
| 060 | 📖 Optimizing Java Application Performance | ★☆☆ | Start Lab |
| 061 | 📖 Java Float isInfinite Method | ★☆☆ | Start Lab |
| 062 | 📖 Java Float shortValue Method | ★☆☆ | Start Lab |
| 063 | 📖 Java Localdate Tostring Method | ★☆☆ | Start Lab |
| 064 | 📖 Conversion Between String and Byte Array | ★☆☆ | Start Lab |
| 065 | 📖 Java LocalDate Get Method | ★☆☆ | Start Lab |
| 066 | 📖 Java LocalDate isBefore Method | ★☆☆ | Start Lab |
| 067 | 📖 Java Character CodePointAt Char Int Int Method | ★☆☆ | Start Lab |
| 068 | 📖 Integer Division in Java | ★☆☆ | Start Lab |
| 069 | 📖 Java Long compareTo Method | ★☆☆ | Start Lab |
| 070 | 📖 Java Long Min Method | ★☆☆ | Start Lab |
| 071 | 📖 Java Character lowSurrogate Method | ★☆☆ | Start Lab |
| 072 | 📖 Java Long Shortvalue Method | ★☆☆ | Start Lab |
| 073 | 📖 Spy in Mockito | ★☆☆ | Start Lab |
| 074 | 📖 Java Character toCodePoint Method | ★☆☆ | Start Lab |
| 075 | 📖 Java LocalDate ofYearDay Method | ★☆☆ | Start Lab |
| 076 | 📖 Convert Array to List | ★☆☆ | Start Lab |
| 077 | 📖 Java Integer reverseBytes Method | ★☆☆ | Start Lab |
| 078 | 📖 Convert Double to String | ★☆☆ | Start Lab |
| 079 | 📖 Java Double IsFinite Method | ★☆☆ | Start Lab |
| 080 | 📖 How to Join Arrays | ★☆☆ | Start Lab |
| 081 | 📖 Java Integer Decode Method | ★☆☆ | Start Lab |
| 082 | 📖 Java LocalDate From Method | ★☆☆ | Start Lab |
| 083 | 📖 Java LocalDate ofEpochDay Method | ★☆☆ | Start Lab |
| 084 | 📖 Convert Char Array to String | ★☆☆ | Start Lab |
| 085 | 📖 Java Long compareUnsigned Method | ★☆☆ | Start Lab |
| 086 | 📖 Java Float byteValue Method | ★☆☆ | Start Lab |
| 087 | 📖 Java Long.toString Method | ★☆☆ | Start Lab |
| 088 | 📖 Check if a File Exists | ★☆☆ | Start Lab |
| 089 | 📖 Resolving Class Interface or Enum Expected Error | ★☆☆ | Start Lab |
| 090 | 📖 Java LocalDate getYear Method | ★☆☆ | Start Lab |
| 091 | 📖 Deleting a File or Directory | ★☆☆ | Start Lab |
| 092 | 📖 Generating Random Numbers in a Range | ★☆☆ | Start Lab |
| 093 | 📖 Validating Unicode Identifier Start | ★☆☆ | Start Lab |
| 094 | 📖 Java LocalDate getEra Method | ★☆☆ | Start Lab |
| 095 | 📖 Files Last Modified Time | ★☆☆ | Start Lab |
| 096 | 📖 Removing Numeric Values from Java Strings | ★☆☆ | Start Lab |
| 097 | 📖 Java LocalDate toEpochDay Method | ★☆☆ | Start Lab |
| 098 | 📖 Java LocalDate hashCode Method | ★☆☆ | Start Lab |
| 099 | 📖 String Substring Search in Java | ★☆☆ | Start Lab |
| 100 | 📖 Java Character forDigit Method | ★☆☆ | Start Lab |
| 101 | 📖 Convert Java String to Array | ★☆☆ | Start Lab |
| 102 | 📖 Determining Space Characters in Java | ★☆☆ | Start Lab |
| 103 | 📖 Java Character valueOf Method | ★☆☆ | Start Lab |
| 104 | 📖 Java Integer toUnsignedString Method | ★☆☆ | Start Lab |
| 105 | 📖 Java Character isValidCodePoint Method | ★☆☆ | Start Lab |
| 106 | 📖 How to Find Maximum Value Map | ★☆☆ | Start Lab |
| 107 | 📖 Sorting ArrayList in Java | ★☆☆ | Start Lab |
| 108 | 📖 Creating Copy Constructors in Java | ★☆☆ | Start Lab |
| 109 | 📖 Check File Readability and Writability | ★☆☆ | Start Lab |
| 110 | 📖 How to Call a Method | ★☆☆ | Start Lab |
| 111 | 📖 Java Float Min Method | ★☆☆ | Start Lab |
| 112 | 📖 Java Integer Divideunsigned Method | ★☆☆ | Start Lab |
| 113 | 📖 Character Frequency in Java Strings | ★☆☆ | Start Lab |
| 114 | 📖 Java Array Initialization Techniques | ★☆☆ | Start Lab |
| 115 | 📖 Java Float Compare Method | ★☆☆ | Start Lab |
| 116 | 📖 Java Character getNumericValue Method | ★☆☆ | Start Lab |
| 117 | 📖 Java Character isLetterOrDigit Method | ★☆☆ | Start Lab |
| 118 | 📖 Convert Character to Title Case | ★☆☆ | Start Lab |
| 119 | 📖 Bitwise XOR Operator in Java | ★☆☆ | Start Lab |
| 120 | 📖 Java Character isISOControl Method | ★☆☆ | Start Lab |
| 121 | 📖 Java Double isInfinite Method | ★☆☆ | Start Lab |
| 122 | 📖 Java LocalDate withDayOfYear Method | ★☆☆ | Start Lab |
| 123 | 📖 Java Double Sum Method | ★☆☆ | Start Lab |
| 124 | 📖 Java LocalDate compareTo Method | ★☆☆ | Start Lab |
| 125 | 📖 Java Long Reverse Bytes Method | ★☆☆ | Start Lab |
| 126 | 📖 Java Float floatToRawIntBits Method | ★☆☆ | Start Lab |
| 127 | 📖 Create ArrayList From Array | ★☆☆ | Start Lab |
| 128 | 📖 How to Repeat a String N Times | ★☆☆ | Start Lab |
| 129 | 📖 Identifying Ignorable Java Characters | ★☆☆ | Start Lab |
| 130 | 📖 Java DoubleToLongBits Method | ★☆☆ | Start Lab |
| 131 | 📖 Java Integer longValue Method | ★☆☆ | Start Lab |
| 132 | 📖 Java Integer RotateLeft Method | ★☆☆ | Start Lab |
| 133 | 📖 Java Integer ValueOf Method | ★☆☆ | Start Lab |
| 134 | 📖 Java Long Decode Method | ★☆☆ | Start Lab |
| 135 | 📖 Adding a Newline Character to a String | ★☆☆ | Start Lab |
| 136 | 📖 Convert String to ArrayList | ★☆☆ | Start Lab |
| 137 | 📖 Java Character IsLetter Method | ★☆☆ | Start Lab |
| 138 | 📖 Identify Unicode Identifier Parts in Java | ★☆☆ | Start Lab |
| 139 | 📖 Java Character isWhitespace Method | ★☆☆ | Start Lab |
| 140 | 📖 Java Long Compare Method | ★☆☆ | Start Lab |
| 141 | 📖 Formatting with Printf | ★☆☆ | Start Lab |
| 142 | 📖 Java Character reverseBytes Method | ★☆☆ | Start Lab |
| 143 | 📖 Java LocalDate withMonth Method | ★☆☆ | Start Lab |
| 144 | 📖 Convert String to Byte | ★☆☆ | Start Lab |
| 145 | 📖 Java Integer numberOfTrailingZeros Method | ★☆☆ | Start Lab |
| 146 | 📖 Java Integer RemainderUnsigned Method | ★☆☆ | Start Lab |
| 147 | 📖 Java Long doubleValue Method | ★☆☆ | Start Lab |
| 148 | 📖 Java Long Reverse Method | ★☆☆ | Start Lab |
| 149 | 📖 Java Localdate Getdayofweek Method | ★☆☆ | Start Lab |
| 150 | 📖 Java Integer floatValue Method | ★☆☆ | Start Lab |
| 151 | 📖 Creating Custom Java Exceptions | ★☆☆ | Start Lab |
| 152 | 📖 Java Long Signum Method | ★☆☆ | Start Lab |
| 153 | 📖 Single Line List Initialization | ★☆☆ | Start Lab |
| 154 | 📖 Java ArrayList to HashSet Conversion | ★☆☆ | Start Lab |
| 155 | 📖 Writing a File | ★☆☆ | Start Lab |
| 156 | 📖 Java 8 Date and Time API | ★☆☆ | Start Lab |
| 157 | 📖 Java Integer rotateRight Method | ★☆☆ | Start Lab |
| 158 | 📖 Java Json Libraries | ★☆☆ | Start Lab |
| 159 | 📖 Checking if a String Is Numeric | ★☆☆ | Start Lab |
| 160 | 📖 Modulo Operator in Java | ★☆☆ | Start Lab |
| 161 | 📖 Java Character toUpperCase Method | ★☆☆ | Start Lab |
| 162 | 📖 Checking Lowercase Characters in Java | ★☆☆ | Start Lab |
| 163 | 📖 Java Integer Reverse Method | ★☆☆ | Start Lab |
| 164 | 📖 Java Long Max Method | ★☆☆ | Start Lab |
| 165 | 📖 Java LocalDate GetDayOfYear Method | ★☆☆ | Start Lab |
| 166 | 📖 Learn Current Local Date | ★☆☆ | Start Lab |
| 167 | 📖 Convert Integer List to Int Array | ★☆☆ | Start Lab |
| 168 | 📖 Read XML File | ★☆☆ | Start Lab |
| 169 | 📖 Identifying Ignorable Unicode Characters | ★☆☆ | Start Lab |
| 170 | 📖 Java Integer to Binary Conversion | ★☆☆ | Start Lab |
| 171 | 📖 Java Double toHexString Method | ★☆☆ | Start Lab |
| 172 | 📖 Java Integer shortValue Method | ★☆☆ | Start Lab |
| 173 | 📖 Read a CSV File | ★☆☆ | Start Lab |
| 174 | 📖 How to Convert Stream to an Array | ★☆☆ | Start Lab |
| 175 | 📖 Java Character Digit Method | ★☆☆ | Start Lab |
| 176 | 📖 Exploring Java Character Space Detection | ★☆☆ | Start Lab |
| 177 | 📖 Convert Unicode Code Point to Title Case | ★☆☆ | Start Lab |
| 178 | 📖 Java Double Min Method | ★☆☆ | Start Lab |
| 179 | 📖 Java Float intBitsToFloat Method | ★☆☆ | Start Lab |
| 180 | 📖 Java Float intValue Method | ★☆☆ | Start Lab |
| 181 | 📖 Java Long numberOfTrailingZeros Method | ★☆☆ | Start Lab |
| 182 | 📖 Java Long parseUnsignedLong Method | ★☆☆ | Start Lab |
| 183 | 📖 Java Long remainderUnsigned Method | ★☆☆ | Start Lab |
| 184 | 📖 Remove Element From a Java Map | ★☆☆ | Start Lab |
| 185 | 📖 Sort HashSet Elements | ★☆☆ | Start Lab |
| 186 | 📖 Identifying Java Identifier Start Characters | ★☆☆ | Start Lab |
| 187 | 📖 Determining Titlecase Characters in Java | ★☆☆ | Start Lab |
| 188 | 📖 Java Float floatValue Method | ★☆☆ | Start Lab |
| 189 | 📖 Java Long toHexString Method | ★☆☆ | Start Lab |
| 190 | 📖 Recursive Merge Sort Implementation in Java | ★☆☆ | Start Lab |
| 191 | 📖 How to Convert String Date to Timestamp | ★☆☆ | Start Lab |
| 192 | 📖 Java Character isJavaIdentifierPart Method | ★☆☆ | Start Lab |
| 193 | 📖 Java Integer CompareUnsigned Method | ★☆☆ | Start Lab |
| 194 | 📖 Java Long LowestOneBit Method | ★☆☆ | Start Lab |
| 195 | 📖 Java Float isNaN Method | ★☆☆ | Start Lab |
| 196 | 📖 Java Float parseFloat Method | ★☆☆ | Start Lab |
| 197 | 📖 Convert Unicode Code Point to Lowercase | ★☆☆ | Start Lab |
| 198 | 📖 JLambda Expressions and Stream API | ★☆☆ | Start Lab |
| 199 | 📖 Java Integer Min Method | ★☆☆ | Start Lab |
| 200 | 📖 How to Join Two ArrayList | ★☆☆ | Start Lab |
| 201 | 📖 Exploring Java Character Title Case Method | ★☆☆ | Start Lab |
| 202 | 📖 Substring Replacement in Java | ★☆☆ | Start Lab |
| 203 | 📖 Java Integer toUnsignedLong Method | ★☆☆ | Start Lab |
| 204 | 📖 Java Long toOctalString Method | ★☆☆ | Start Lab |
| 205 | 📖 Reverse String in Java | ★☆☆ | Start Lab |
| 206 | 📖 Java Math Pow Method | ★☆☆ | Start Lab |
| 207 | 📖 Counting Unicode Code Points in Char Array | ★☆☆ | Start Lab |
| 208 | 📖 Converting Between an Array and List | ★☆☆ | Start Lab |
| 209 | 📖 Convert Char to String | ★☆☆ | Start Lab |
| 210 | 📖 Implementing a Binary Search Tree | ★☆☆ | Start Lab |
| 211 | 📖 Identifying Unicode Identifier Start Characters | ★☆☆ | Start Lab |
| 212 | 📖 Java Float to String Conversion | ★☆☆ | Start Lab |
| 213 | 📖 Copy Files Using Java Files Class | ★☆☆ | Start Lab |
| 214 | 📖 How to Join Strings | ★☆☆ | Start Lab |
| 215 | 📖 Check if Input Is Integer | ★☆☆ | Start Lab |
| 216 | 📖 Check if Directory Exists | ★☆☆ | Start Lab |
| 217 | 📖 Java Character getName Method | ★☆☆ | Start Lab |
| 218 | 📖 Java ArrayList to LinkedHashSet Conversion | ★☆☆ | Start Lab |
| 219 | 📖 Convert Int to String | ★☆☆ | Start Lab |
| 220 | 📖 How to Get File Extension | ★☆☆ | Start Lab |
| 221 | 📖 Java Integer Hashcode Method | ★☆☆ | Start Lab |
| 222 | 📖 Java Integer Equals Method | ★☆☆ | Start Lab |
| 223 | 📖 Implementing Dijkstra's Algorithm | ★☆☆ | Start Lab |
| 224 | 📖 Convert List to Array | ★☆☆ | Start Lab |
| 225 | 📖 Introduction to Orgjson | ★☆☆ | Start Lab |
| 226 | 📖 Java Character hashCode Method | ★☆☆ | Start Lab |
| 227 | 📖 Generating Float hashCode in Java | ★☆☆ | Start Lab |
| 228 | 📖 Java Character isLowSurrogate Method | ★☆☆ | Start Lab |
| 229 | 📖 Java Integer intValue Method | ★☆☆ | Start Lab |
| 230 | 📖 Java Integer parseInt Method | ★☆☆ | Start Lab |
| 231 | 📖 Java Integer parseUnsignedInt Method | ★☆☆ | Start Lab |
| 232 | 📖 Java Integer ValueOf String Method | ★☆☆ | Start Lab |
| 233 | 📖 Java Long parseLong Method | ★☆☆ | Start Lab |
| 234 | 📖 Java Long Unsigned String Conversion | ★☆☆ | Start Lab |
| 235 | 📖 Rounding Floating-Point Numbers in Java | ★☆☆ | Start Lab |
| 236 | 📖 Java Double Equals Method | ★☆☆ | Start Lab |
| 237 | 📖 Java Character Codepointat Charsequence Int Method | ★☆☆ | Start Lab |
| 238 | 📖 Convert Integer to String in Java | ★☆☆ | Start Lab |
| 239 | 📖 Java Formatting Strings | ★☆☆ | Start Lab |
| 240 | 📖 Counting Unicode Code Points | ★☆☆ | Start Lab |
| 241 | 📖 Java Double parseDouble Method | ★☆☆ | Start Lab |
| 242 | 📖 Convert Character to String | ★☆☆ | Start Lab |
| 243 | 📖 Java Double Max Method | ★☆☆ | Start Lab |
| 244 | 📖 Count Occurrences of a Character | ★☆☆ | Start Lab |
| 245 | 📖 Java Character Equals Method | ★☆☆ | Start Lab |
| 246 | 📖 Java Character GetType Codepoint Method | ★☆☆ | Start Lab |
| 247 | 📖 Checking Palindromes in Java | ★☆☆ | Start Lab |
| 248 | 📖 Utilizing Pairs in Java Programming | ★☆☆ | Start Lab |
| 249 | 📖 Converting ArrayList to LinkedList | ★☆☆ | Start Lab |
| 250 | 📖 Java Generics Concepts | ★☆☆ | Start Lab |
| 251 | 📖 Java Character isSurrogate Method | ★☆☆ | Start Lab |
| 252 | 📖 Java Character Code Point to String | ★☆☆ | Start Lab |
| 253 | 📖 Java Float toString Method | ★☆☆ | Start Lab |
| 254 | 📖 Java Heap Memory Error | ★☆☆ | Start Lab |
| 255 | 📖 Add Elements to Array and ArrayList | ★☆☆ | Start Lab |
| 256 | 📖 Immutable Strings in Java Programming | ★☆☆ | Start Lab |
| 257 | 📖 Java Binary Search | ★☆☆ | Start Lab |
| 258 | 📖 Converting Character to String | ★☆☆ | Start Lab |
| 259 | 📖 Java Integer String Representation | ★☆☆ | Start Lab |
| 260 | 📖 Parse Unsigned Integer | ★☆☆ | Start Lab |
| 261 | 📖 Sorting Techniques in Java | ★☆☆ | Start Lab |
| 262 | 📖 Java Enum Fundamentals | ★☆☆ | Start Lab |
| 263 | 📖 Sorting a HashMap | ★☆☆ | Start Lab |
| 264 | 📖 Efficient QuickSort Divide-and-Conquer Algorithm | ★☆☆ | Start Lab |
| 265 | 📖 Convert Long To String | ★☆☆ | Start Lab |
| 266 | 📖 How to Read a File to String | ★☆☆ | Start Lab |
| 267 | 📖 Sorting Java Map by Values | ★☆☆ | Start Lab |
| 268 | 📖 Introduction to Java Tuples | ★☆☆ | Start Lab |
| 269 | 📖 Graph Data Structures in Java | ★☆☆ | Start Lab |
| 270 | 📖 Remove Duplicates From ArrayList | ★☆☆ | Start Lab |
| 271 | 📖 Java Long toString Exploration | ★☆☆ | Start Lab |
| 272 | 📖 Creating a Swap Function | ★☆☆ | Start Lab |
| 273 | 📖 Efficient Text Processing with Java BufferedReader | ★☆☆ | Start Lab |
| 274 | 📖 Java Assertions: Testing Assumptions | ★☆☆ | Start Lab |
| 275 | 📖 Java TreeMap Data Structure | ★☆☆ | Start Lab |
| 276 | 📖 Shallow vs. Deep Object Copying | ★☆☆ | Start Lab |
| 277 | 📖 Java Float Hashcode Exploration | ★☆☆ | Start Lab |
| 278 | 📖 How to Convert Enum to String | ★☆☆ | Start Lab |
| 279 | 📖 Comparator and Comparable | ★☆☆ | Start Lab |
| 280 | 📖 Convert InputStream to String | ★☆☆ | Start Lab |
| 281 | 📖 How to Create an Object | ★☆☆ | Start Lab |
| 282 | 📖 Java Hashing and HashCode | ★☆☆ | Start Lab |
| 283 | 📖 Java POJO Class | ★☆☆ | Start Lab |
| 284 | 📖 Java Serialization and Deserialization | ★☆☆ | Start Lab |
| 285 | 📖 Reading a CSV File | ★☆☆ | Start Lab |
| 286 | 📖 Java Stream Filter | ★☆☆ | Start Lab |
| 287 | 📖 Java String Concatenation | ★☆☆ | Start Lab |
| 288 | 📖 Sorting Strings in Java using Arrays.sort() | ★☆☆ | Start Lab |
| 289 | 📖 Java 11 New Features | ★☆☆ | Start Lab |