When working with wildcards in generics in Java, we sometimes see a “capture of ?” compile-time error. Learn what a “capture” is, in which cases we see such an error message, and how we can solve the problem.
Also find me here:
Baeldung Author
Michael Krimgen
I'm a Java Software Developer with 12 years experience in the financial industry. I like clean coding, learning new languages (both programming and natural languages) and reading about and understanding algorithms. My main focus is Java, Java EE, Spring, Databases and Kotlin.
Here's what I've written (so far):
Baeldung on Java
- All
- Java (2)
- Core Java (2)
- Algorithms (2)
- Testing (1)
- Spring Web (1)
- Persistence (1)
- Java Map (1)
- Java Dates (1)
- Java Concurrency (1)
- Java Collections (1)
- Java Array (1)
- JVM (1)
Storing Date and Time in PostgreSQL Using Java
Filed under Java Dates, Persistence
A quick tutorial on saving Java dates and times in PostgreSQL.
Find the Kth Smallest Element in Two Sorted Arrays in Java
Filed under Algorithms, Java Array
A quick and practical guide to finding the k-th smallest element in two sorted arrays.
Introduction to Lock-Free Data Structures with Java Examples
Filed under Algorithms, Java, Java Concurrency
A quick and practical guide to lock-free data structures in Java.
Cucumber Hooks
Filed under Testing
Learn about the @Before, @BeforeStep, @AfterStep, and @After Cucumber hooks
Overflow and Underflow in Java
Filed under Java
A quick and practical overview of overflow and underflow in Java.
A Guide to Java HashMap
Filed under Java Map
A quick and practical overview of Java HashMap.
Spring Request Parameters with Thymeleaf
Filed under Spring Web
Learn how to use request parameters with Spring and Thymeleaf.
The Difference Between Collection.stream().forEach() and Collection.forEach()
Filed under Java Collections
A quick and practical overview of the difference between Collection.stream().forEach() and Collection.forEach().
Baeldung on Computer Science
- All
- Trees (1)
- Programming (1)
- Data Structures (1)
- Algorithms (1)
Algorithm to Generate a Maze
Filed under Algorithms
Explore algorithms for generating a maze with visual representations.
What Is an Idempotent Operation?
Filed under Programming
A quick and practical introduction to idempotency.
Introduction to Red-Black Trees
Filed under Data Structures, Trees
A quick and practical overview of the Red-Black Tree data structure.
Baeldung on Kotlin
- All
- Kotlin-Java Interop (2)
- Kotlin Basics (1)
The Difference between var in Kotlin and Java 10
Filed under Kotlin-Java Interop
A quick and practical overview of differences between var keyword in Java and Kotlin.
Guide to JVM Platform Annotations in Kotlin
Filed under Kotlin-Java Interop
Have a look at the @Jvm annotations that Kotlin provides
Nested forEach in Kotlin
Filed under Kotlin Basics
Learn how to use the default parameter it in Kotlin and how to access the parameters of an outer forEach from within a nested forEach loop.