27 articles
RSSHow to fix Lambda SnapStart errors — feature requires published version, $LATEST not supported, restore hook for stale connections, UUID collisions after snapshot, time-based state staleness, and pricing surprises.
How to fix Java record issues — compact constructor validation, custom accessor methods, Jackson serialization, inheritance restrictions, and when to use records vs regular classes.
How to fix OpenTelemetry issues — SDK initialization order, auto-instrumentation setup, OTLP exporter configuration, context propagation, and missing spans in Node.js, Python, and Java.
How to fix Spring Boot test issues — @SpringBootTest vs test slices, MockMvc setup, @MockBean vs @Mock, test context caching, and common test configuration mistakes.
How to fix Spring Boot @Cacheable issues — @EnableCaching missing, self-invocation bypass, key generation, TTL configuration, cache eviction, and Caffeine vs Redis setup.
How to fix Spring Data JPA query issues — JPQL vs native SQL, derived method naming, @Modifying for updates, pagination, projections, and LazyInitializationException.
How to fix Spring @Transactional not rolling back — checked vs unchecked exceptions, self-invocation proxy bypass, rollbackFor, transaction propagation, and nested transactions.
How to fix Hibernate LazyInitializationException — loading lazy associations outside an active session, fetch join, @Transactional scope, DTO projection, and Open Session in View.
How to fix 'Failed to configure a DataSource: url attribute is not specified' in Spring Boot — adding database properties, excluding DataSource auto-configuration, H2 vs production DB setup, and multi-datasource configuration.
How to fix Spring Boot circular dependency errors — BeanCurrentlyInCreationException, refactoring to break cycles, @Lazy injection, setter injection, and @PostConstruct patterns.
How to fix Spring Security 403 Forbidden errors — CSRF token missing, incorrect security configuration, method security blocking requests, and how to debug the Spring Security filter chain.
How to fix Spring Boot 'Failed to configure a DataSource' errors — missing URL property, driver class not found, connection refused, and how to correctly configure datasource properties for MySQL, PostgreSQL, and H2.
How to fix Gradle's 'Could not resolve all dependencies' error caused by missing repositories, offline mode, proxy issues, version conflicts, and corrupted cache.
How to fix Java ClassCastException by using instanceof checks, fixing generic type erasure, resolving ClassLoader conflicts, correcting raw types, and using pattern matching in Java 16+.
How to fix Java ConcurrentModificationException caused by modifying a collection while iterating, HashMap concurrent access, stream operations, and multi-threaded collection usage.
How to fix Java IllegalArgumentException caused by null arguments, invalid enum values, negative numbers, wrong format strings, and Spring/Hibernate validation failures.
How to fix Java NoSuchMethodError caused by classpath conflicts, incompatible library versions, wrong dependency scope, shaded JARs, and compile vs runtime version mismatches.
How to fix Java NullPointerException by reading stack traces, adding null checks, using Optional, fixing uninitialized variables, avoiding null returns, handling auto-unboxing, and using static analysis annotations.
How to fix Spring BeanCreationException error creating bean caused by missing dependencies, circular references, wrong annotations, configuration errors, and constructor issues.
How to fix java.lang.StackOverflowError caused by infinite recursion, circular references in toString or equals, JPA bidirectional relationships, and Spring circular dependencies.
How to fix Java UnsupportedClassVersionError caused by compiling with a newer JDK than the runtime, JAVA_HOME misconfiguration, and Maven/Gradle target version settings.
How to fix Maven's 'Could not resolve dependencies' and 'Failed to read artifact descriptor' errors caused by corrupted cache, proxy settings, missing repositories, and version conflicts.
How to fix the Spring Boot error 'Web server failed to start. Port 8080 was already in use' by killing blocking processes, changing ports, fixing IDE issues, and resolving Docker conflicts.
How to fix the Spring Boot Whitelabel Error Page caused by missing controller mappings, wrong component scan, wrong package structure, and missing Thymeleaf templates.
How to fix Gradle build failures including dependency resolution errors, compilation failures, incompatible Java versions, and daemon issues.
How to fix Java OutOfMemoryError including heap space, Metaspace, GC overhead limit exceeded, and unable to create new native thread.
How to fix Java ClassNotFoundException at runtime by resolving missing dependencies, classpath issues, Maven/Gradle configuration, JDBC drivers, classloader problems, and Java module system errors.