java

Collection modified during iteration

java\.util\.ConcurrentModificationException

Fixes

1.Use Iterator.remove() instead of Collection.remove() during iteration
2.Use ConcurrentHashMap or CopyOnWriteArrayList for concurrent access
3.Create a copy of the collection before iterating

concurrencycollections

Related Errors

Spring Boot bean not found in application context

NoSuchBeanDefinitionException.*No qualifying bean of type

•Add @Component/@Service/@Repository annotation to the class
•Ensure the package is scanned: check @ComponentScan or @SpringBootApplication basePackages

Spring circular dependency during bean creation

BeanCurrentlyInCreationException.*Requested bean is currently in creation

•Use @Lazy annotation on one of the circular dependencies
•Refactor to break the circular dependency with an event or interface

Spring Boot unsatisfied dependency injection

UnsatisfiedDependencyException.*Error creating bean with name

•Verify the required bean exists and is properly annotated
•Use @Qualifier to disambiguate when multiple beans of same type exist