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Practice Java programming through 200+ hands-on coding challenges. Perfect for beginners to advance their skills with real-world projects covering data structures, algorithms, OOP, and core Java concepts.
| Index | Name | Difficulty | Practice |
|---|---|---|---|
| 001 | 🎯 Accessing Elements in a LinkedList | Beginner | Start Challenge |
| 002 | 🎯 Accessing Elements of a HashMap | Beginner | Start Challenge |
| 003 | 🎯 Accessing Static Properties from Another Class | Beginner | Start Challenge |
| 004 | 🎯 Checking String Equality | Beginner | Start Challenge |
| 005 | 🎯 Create Linked List with Index | Beginner | Start Challenge |
| 006 | 🎯 Finding Minimum and Maximum Student Marks | Beginner | Start Challenge |
| 007 | 🎯 Implement Deque Data Structure | Beginner | Start Challenge |
| 008 | 🎯 Implementing Lambda Expression with Parameters | Beginner | Start Challenge |
| 009 | 🎯 Implementing Multilevel Inheritance | Beginner | Start Challenge |
| 010 | 🎯 Remove Second Element From ArrayList | Beginner | Start Challenge |
| 011 | 🎯 Sort Players' Ages Ascending Order | Beginner | Start Challenge |
| 012 | 🎯 Class Methods Retriever Information | Beginner | Start Challenge |
| 013 | 🎯 Concurrent Execution of Threads | Beginner | Start Challenge |
| 014 | 🎯 Counting Character Occurrences | Beginner | Start Challenge |
| 015 | 🎯 Custom Regular Expression | Beginner | Start Challenge |
| 016 | 🎯 Data Sharing Problem in Ticketing System | Beginner | Start Challenge |
| 017 | 🎯 Default Methods in Multiple Interfaces | Beginner | Start Challenge |
| 018 | 🎯 Draw Geometric Shapes | Beginner | Start Challenge |
| 019 | 🎯 From One-Fourth to 0 | Beginner | Start Challenge |
| 020 | 🎯 Implementing Queue Manually | Beginner | Start Challenge |
| 021 | 🎯 Lambda Expressions For Data Operations | Beginner | Start Challenge |
| 022 | 🎯 Matrix element information printing | Beginner | Start Challenge |
| 023 | 🎯 Remove Duplicate Numbers | Beginner | Start Challenge |
| 024 | 🎯 Set a price for attractions tickets | Beginner | Start Challenge |
| 025 | 🎯 Sibling Money Division Game | Beginner | Start Challenge |
| 026 | 🎯 Simulating a Library | Beginner | Start Challenge |
| 027 | 🎯 Solving Apple Distribution Problem with Exceptions | Beginner | Start Challenge |
| 028 | 🎯 Storing Data Information Using HashSet | Beginner | Start Challenge |
| 029 | 🎯 Sum of Large Numbers | Beginner | Start Challenge |
| 030 | 🎯 Sum of Three-Digit Number's Digits | Beginner | Start Challenge |
| 031 | 🎯 The Only God | Beginner | Start Challenge |
| 032 | 🎯 Usage of Stream | Beginner | Start Challenge |
| 033 | 🎯 Validating ID Card Number | Beginner | Start Challenge |
| 034 | 🎯 Simple Java Print Statement | Beginner | Start Challenge |
| 035 | 🎯 Implement Encryption and Decryption | Beginner | Start Challenge |
| 036 | 🎯 Access and Modify Student Name | Beginner | Start Challenge |
| 037 | 🎯 Accessing Overridden Method of Superclass | Beginner | Start Challenge |
| 038 | 🎯 Accessing Static Properties in a Class | Beginner | Start Challenge |
| 039 | 🎯 Accessing Superclass Constructor | Beginner | Start Challenge |
| 040 | 🎯 Adding Elements to ArrayList | Beginner | Start Challenge |
| 041 | 🎯 Adding Elements to ArrayLists at Specific Index | Beginner | Start Challenge |
| 042 | 🎯 Area Calculation Program using Abstraction | Beginner | Start Challenge |
| 043 | 🎯 Calculate BMI Using Weight and Height | Beginner | Start Challenge |
| 044 | 🎯 Calculate Cube Volume From Side | Beginner | Start Challenge |
| 045 | 🎯 Calculate Employee Bonus Based Salary | Beginner | Start Challenge |
| 046 | 🎯 Calculate Interest Based on Principal | Beginner | Start Challenge |
| 047 | 🎯 Calculate Mean Height of Players | Beginner | Start Challenge |
| 048 | 🎯 Calculate Percentage with Arrays | Beginner | Start Challenge |
| 049 | 🎯 Calculate Rectangle Area Using Class | Beginner | Start Challenge |
| 050 | 🎯 Calculate Rectangle Dimensions | Beginner | Start Challenge |
| 051 | 🎯 Calculate Sum of Digits | Beginner | Start Challenge |
| 052 | 🎯 Calculate the Factorial of a Number | Beginner | Start Challenge |
| 053 | 🎯 Calculating Area of Two Triangles | Beginner | Start Challenge |
| 054 | 🎯 Calculating Power of a Number | Beginner | Start Challenge |
| 055 | 🎯 Calculating Standard Deviation in Java | Beginner | Start Challenge |
| 056 | 🎯 Calculating Sum of Natural Numbers | Beginner | Start Challenge |
| 057 | 🎯 Calculating the Area of a Circle | Beginner | Start Challenge |
| 058 | 🎯 Calculating the Area of a Square | Beginner | Start Challenge |
| 059 | 🎯 Calling a Method Twice | Beginner | Start Challenge |
| 060 | 🎯 Check Pass, Fail, or Invalid | Beginner | Start Challenge |
| 061 | 🎯 Checking IcyHot Temperature Using Java | Beginner | Start Challenge |
| 062 | 🎯 Comparing First and Last Array Elements | Beginner | Start Challenge |
| 063 | 🎯 Continuously Sum Entered Numbers | Beginner | Start Challenge |
| 064 | 🎯 Convert Between Kilometers and Miles Using Java | Beginner | Start Challenge |
| 065 | 🎯 Count the Vowels in a String | Beginner | Start Challenge |
| 066 | 🎯 Counting Digits In An Integer | Beginner | Start Challenge |
| 067 | 🎯 Counting Occurrences of Character 'a' | Beginner | Start Challenge |
| 068 | 🎯 Create a Calculator Program | Beginner | Start Challenge |
| 069 | 🎯 Creating Enum Class - Size | Beginner | Start Challenge |
| 070 | 🎯 Creating an Animal-Dog Hierarchy | Beginner | Start Challenge |
| 071 | 🎯 Determine Factors of a Number | Beginner | Start Challenge |
| 072 | 🎯 Determine Longer String From Inputs | Beginner | Start Challenge |
| 073 | 🎯 Determine Maximum Handshakes Among Students | Beginner | Start Challenge |
| 074 | 🎯 Determine Student Grade | Beginner | Start Challenge |
| 075 | 🎯 Determining Equality of Two Arguments | Beginner | Start Challenge |
| 076 | 🎯 Determining Even or Odd | Beginner | Start Challenge |
| 077 | 🎯 Determining Harshad Number in Java | Beginner | Start Challenge |
| 078 | 🎯 Determining If a Number is Armstrong | Beginner | Start Challenge |
| 079 | 🎯 Determining Prime Number Status | Beginner | Start Challenge |
| 080 | 🎯 Distribute Chocolates To Children | Beginner | Start Challenge |
| 081 | 🎯 Encapsulating Employee Salary Management | Beginner | Start Challenge |
| 082 | 🎯 Enum Constants as Strings | Beginner | Start Challenge |
| 083 | 🎯 Exclude Multiples of Three from Numbers | Beginner | Start Challenge |
| 084 | 🎯 Fahrenheit to Celsius Conversion Program | Beginner | Start Challenge |
| 085 | 🎯 Find Differences Between Two Hashsets | Beginner | Start Challenge |
| 086 | 🎯 Find Intersection of Two HashSets | Beginner | Start Challenge |
| 087 | 🎯 Find Largest Multiple Less Than 100 | Beginner | Start Challenge |
| 088 | 🎯 Find Smallest Array Element | Beginner | Start Challenge |
| 089 | 🎯 Find Youngest Brother | Beginner | Start Challenge |
| 090 | 🎯 Finding Nemo in ArrayList | Beginner | Start Challenge |
| 091 | 🎯 Finding Prime Numbers in Intervals | Beginner | Start Challenge |
| 092 | 🎯 Finding the GCD of Two Numbers | Beginner | Start Challenge |
| 093 | 🎯 Finding the Lowest Common Multiple | Beginner | Start Challenge |
| 094 | 🎯 FizzBuzz Program: User Input Explanation | Beginner | Start Challenge |
| 095 | 🎯 Generate Multiplication Table Using Loops | Beginner | Start Challenge |
| 096 | 🎯 Greatest Factor Excluding Itself | Beginner | Start Challenge |
| 097 | 🎯 Identify Self-Dividing Numbers | Beginner | Start Challenge |
| 098 | 🎯 Identifying Abundant Numbers Using Java | Beginner | Start Challenge |
| 099 | 🎯 Implement Interface to Calculate Square Area | Beginner | Start Challenge |
| 100 | 🎯 Implementing a Queue Using a LinkedList | Beginner | Start Challenge |
| 101 | 🎯 Method Overloading for Different Parameters | Beginner | Start Challenge |
| 102 | 🎯 Method Overloading with Different Parameter Types | Beginner | Start Challenge |
| 103 | 🎯 Modify Elements in HashMap | Beginner | Start Challenge |
| 104 | 🎯 Modifying an ArrayList with Java | Beginner | Start Challenge |
| 105 | 🎯 Multiple Class Method Overriding | Beginner | Start Challenge |
| 106 | 🎯 Multiple Classes Inheriting a Class | Beginner | Start Challenge |
| 107 | 🎯 Multiply Array By Ten | Beginner | Start Challenge |
| 108 | 🎯 Overload Final Method Demonstration | Beginner | Start Challenge |
| 109 | 🎯 Overriding Parent Class Method | Beginner | Start Challenge |
| 110 | 🎯 Palindrome Number Check | Beginner | Start Challenge |
| 111 | 🎯 Perform Complex Number Addition | Beginner | Start Challenge |
| 112 | 🎯 Pound to Kilogram Conversion Program | Beginner | Start Challenge |
| 113 | 🎯 Primitive Types to Wrapper Classes | Beginner | Start Challenge |
| 114 | 🎯 Print Any Type of Data | Beginner | Start Challenge |
| 115 | 🎯 Print Even Numbers from Array | Beginner | Start Challenge |
| 116 | 🎯 Print Non-Alphabet Characters | Beginner | Start Challenge |
| 117 | 🎯 Print Value of Any Data Type | Beginner | Start Challenge |
| 118 | 🎯 Printing Array Elements | Beginner | Start Challenge |
| 119 | 🎯 Printing Individual Characters in a String | Beginner | Start Challenge |
| 120 | 🎯 Printing a Sentence Three Times | Beginner | Start Challenge |
| 121 | 🎯 Removing Elements from a HashMap | Beginner | Start Challenge |
| 122 | 🎯 Reverse a Number Program | Beginner | Start Challenge |
| 123 | 🎯 Shop Profit/Loss Calculator | Beginner | Start Challenge |
| 124 | 🎯 Simple Interest Calculation Program | Beginner | Start Challenge |
| 125 | 🎯 String Concatenation: Two Texts Combined | Beginner | Start Challenge |
| 126 | 🎯 String Conversion: First Letter Uppercase | Beginner | Start Challenge |
| 127 | 🎯 Subtraction of Coordinates | Beginner | Start Challenge |
| 128 | 🎯 Swapping Two Numbers with Temp | Beginner | Start Challenge |
| 129 | 🎯 Valid Internal Angles of Triangle | Beginner | Start Challenge |
| 130 | 🎯 Validate Leap Year Condition | Beginner | Start Challenge |
| 131 | 🎯 Verify Prime Number Status Using Java | Beginner | Start Challenge |
| 132 | 🎯 Verifying Class Instance | Beginner | Start Challenge |
| 133 | 🎯 Voting Eligibility Determination Program | Beginner | Start Challenge |
| 134 | 🎯 Airplane Battle Game | Beginner | Start Challenge |
| 135 | 🎯 Alien Cell Fission | Beginner | Start Challenge |
| 136 | 🎯 Area of Circle with Any Radius | Beginner | Start Challenge |
| 137 | 🎯 Automotive Sales Market | Beginner | Start Challenge |
| 138 | 🎯 Bank Account Program | Beginner | Start Challenge |
| 139 | 🎯 Blossoms Compete for Beauty | Beginner | Start Challenge |
| 140 | 🎯 Building and Deploying Spring Boot | Beginner | Start Challenge |
| 141 | 🎯 Business Card Distribution | Beginner | Start Challenge |
| 142 | 🎯 Caesar Cipher Encryption | Beginner | Start Challenge |
| 143 | 🎯 Calculating the Volume of a Cube | Beginner | Start Challenge |
| 144 | 🎯 Calculating the Volume of a Cylinder | Beginner | Start Challenge |
| 145 | 🎯 Chat Room Simulation | Beginner | Start Challenge |
| 146 | 🎯 Class Grade Ranking | Beginner | Start Challenge |
| 147 | 🎯 Class Properties and Methods | Beginner | Start Challenge |
| 148 | 🎯 Classify Words by Parts of Speech | Beginner | Start Challenge |
| 149 | 🎯 Coexisting Chicken and Rabbit Cage | Beginner | Start Challenge |
| 150 | 🎯 Configuration File Content | Beginner | Start Challenge |
| 151 | 🎯 Configuring Class Parameters with Annotations | Beginner | Start Challenge |
| 152 | 🎯 Counting the Occurrences of a Substring | Beginner | Start Challenge |
| 153 | 🎯 Define Your Annotations | Beginner | Start Challenge |
| 154 | 🎯 Design and Implementation of Graphic Interface | Beginner | Start Challenge |
| 155 | 🎯 Design and Implementation of Multiple Interfaces | Beginner | Start Challenge |
| 156 | 🎯 Determine Spaceship Return Feasibility | Beginner | Start Challenge |
| 157 | 🎯 Determine Triangle Feasibility with Exception Hand... | Beginner | Start Challenge |
| 158 | 🎯 Dining Philosophers Synchronization | Beginner | Start Challenge |
| 159 | 🎯 Displaying Data Information Using Iterator | Beginner | Start Challenge |
| 160 | 🎯 Divide Apples with Exception Handling | Beginner | Start Challenge |
| 161 | 🎯 Efficient Student Grade Analysis Program | Beginner | Start Challenge |
| 162 | 🎯 Enter student information | Beginner | Start Challenge |
| 163 | 🎯 Enum Class for Gender Information | Beginner | Start Challenge |
| 164 | 🎯 Fibonacci Sequence Programming | Beginner | Start Challenge |
| 165 | 🎯 File Content Filtering | Beginner | Start Challenge |
| 166 | 🎯 File Upload Based on UDP Protocol | Beginner | Start Challenge |
| 167 | 🎯 Flow Control Statements for Multiple Requirements | Beginner | Start Challenge |
| 168 | 🎯 Fun Code Completion | Beginner | Start Challenge |
| 169 | 🎯 Get Information from Google Homepage | Beginner | Start Challenge |
| 170 | 🎯 Handling Incorrect Grades | Beginner | Start Challenge |
| 171 | 🎯 Hello LabEx Using Java | Beginner | Start Challenge |
| 172 | 🎯 How Many Days in Each Month | Beginner | Start Challenge |
| 173 | 🎯 Implement Countdown Timer Thread | Beginner | Start Challenge |
| 174 | 🎯 Implement a Stock class | Beginner | Start Challenge |
| 175 | 🎯 Implementing Pascal's Triangle | Beginner | Start Challenge |
| 176 | 🎯 Implementing String Split | Beginner | Start Challenge |
| 177 | 🎯 Implementing String Utility Class | Beginner | Start Challenge |
| 178 | 🎯 Intelligent Care Call Service | Beginner | Start Challenge |
| 179 | 🎯 Intersection of Linked Lists | Beginner | Start Challenge |
| 180 | 🎯 Java Engineer Salary Calculation | Beginner | Start Challenge |
| 181 | 🎯 Kong Rong's Generosity | Beginner | Start Challenge |
| 182 | 🎯 Landlord Card Game Simulation Using Java | Beginner | Start Challenge |
| 183 | 🎯 Launching Wayne's Automated Height Calculation | Beginner | Start Challenge |
| 184 | 🎯 Log Information Classification | Beginner | Start Challenge |
| 185 | 🎯 Love at First Sight | Beginner | Start Challenge |
| 186 | 🎯 Maximize Aeroplane Chess Score Using Dynamic Progr... | Beginner | Start Challenge |
| 187 | 🎯 Maximize Airplane Destruction Strategy | Beginner | Start Challenge |
| 188 | 🎯 Maximum value of three numbers. | Beginner | Start Challenge |
| 189 | 🎯 Modify Weapon Design Using Inheritance | Beginner | Start Challenge |
| 190 | 🎯 Narcissistic Number Judgment | Beginner | Start Challenge |
| 191 | 🎯 Navigating Space Bridge with Java Arrays | Beginner | Start Challenge |
| 192 | 🎯 No Money Jewelry Store Marketing | Beginner | Start Challenge |
| 193 | 🎯 Number of Palindromic Numbers | Beginner | Start Challenge |
| 194 | 🎯 Nüwa Creates Humans | Beginner | Start Challenge |
| 195 | 🎯 Obtaining Class Objects of Different Classes | Beginner | Start Challenge |
| 196 | 🎯 Operations with Method References | Beginner | Start Challenge |
| 197 | 🎯 Optimal Coin Selection for Spring Purchase | Beginner | Start Challenge |
| 198 | 🎯 Optimizing Threaded Relay Race Simulation | Beginner | Start Challenge |
| 199 | 🎯 Output a Triangle | Beginner | Start Challenge |
| 200 | 🎯 Outputting Book Info | Beginner | Start Challenge |
| 201 | 🎯 Parsing XML Data Information with DOM | Beginner | Start Challenge |
| 202 | 🎯 Point Inside a Triangle | Beginner | Start Challenge |
| 203 | 🎯 Producer-Consumer Queue Implementation | Beginner | Start Challenge |
| 204 | 🎯 Reflectively Create A Person Object | Beginner | Start Challenge |
| 205 | 🎯 Release Scanner Resource using finally | Beginner | Start Challenge |
| 206 | 🎯 Rescue Princess with Conditional Execution | Beginner | Start Challenge |
| 207 | 🎯 Reverse One-Dimensional Array in Java | Beginner | Start Challenge |
| 208 | 🎯 Reverse Output Word List | Beginner | Start Challenge |
| 209 | 🎯 Reverse Word Order in English Sentences | Beginner | Start Challenge |
| 210 | 🎯 Rewriting the equals method | Beginner | Start Challenge |
| 211 | 🎯 Running Data Alternately In Three Groups | Beginner | Start Challenge |
| 212 | 🎯 SAX Parsing XML Data | Beginner | Start Challenge |
| 213 | 🎯 Searching in a Two-Dimensional Array | Beginner | Start Challenge |
| 214 | 🎯 Servlet User Information Query | Beginner | Start Challenge |
| 215 | 🎯 Simple Student Management System | Beginner | Start Challenge |
| 216 | 🎯 Simulated University Management System | Beginner | Start Challenge |
| 217 | 🎯 Spaceship Speed Control | Beginner | Start Challenge |
| 218 | 🎯 Spare Me, My Lord | Beginner | Start Challenge |
| 219 | 🎯 Spiral Traversal of a Tree | Beginner | Start Challenge |
| 220 | 🎯 Stair Climbing and Balance Prediction | Beginner | Start Challenge |
| 221 | 🎯 Storing Data Information Using TreeSet | Beginner | Start Challenge |
| 222 | 🎯 Strength Training with Accumulative Method | Beginner | Start Challenge |
| 223 | 🎯 String Class Constructors | Beginner | Start Challenge |
| 224 | 🎯 String Information Statistics | Beginner | Start Challenge |
| 225 | 🎯 String class methods | Beginner | Start Challenge |
| 226 | 🎯 Student Management System | Beginner | Start Challenge |
| 227 | 🎯 Student Score Ranking System | Beginner | Start Challenge |
| 228 | 🎯 Substring Occurrence Count | Beginner | Start Challenge |
| 229 | 🎯 Summoning Elves Gameplay | Beginner | Start Challenge |
| 230 | 🎯 The Magical Pocket | Beginner | Start Challenge |
| 231 | 🎯 The Wall Has Ears | Beginner | Start Challenge |
| 232 | 🎯 The Wandering Earth | Beginner | Start Challenge |
| 233 | 🎯 The Wish of Five Cents | Beginner | Start Challenge |
| 234 | 🎯 Understanding Constant Pool | Beginner | Start Challenge |
| 235 | 🎯 User Registration Validation with Exceptions | Beginner | Start Challenge |
| 236 | 🎯 Using Inheritance to Save Code | Beginner | Start Challenge |
| 237 | 🎯 When Can I Save Enough Money | Beginner | Start Challenge |
| 238 | 🎯 Writing Objects to File | Beginner | Start Challenge |
| 239 | 🎯 Yin and Yang | Beginner | Start Challenge |
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. With a strict 'Learn by Doing' approach, interactive online environments in the browser with automated step-by-step checks, structured content organization through the Skill Tree learning system, and a growing resource of 30 Skill Trees and over 6,000 Labs, LabEx offers comprehensive practical education. The platform includes Labby, an AI learning assistant built on latest AI models, providing a conversational learning experience.