Use numbers, text, booleans, variables, operators, and simple input to make programs respond to data.

Use if statements, switch, loops, and boolean logic to make programs choose paths and repeat work.

Break programs into named methods, pass values in, return results, and keep code readable as it grows.

Read compiler messages, trace runtime failures, use breakpoints, and fix small programs without guessing.

Follow Java’s path from applets and enterprise servers to open-source OpenJDK, faster release cycles, cloud services, and modern language features.

Create classes, fields, constructors, and objects to model real things in code.

Use access modifiers, getters, setters, final fields, and immutability to protect objects from accidental damage.

Use interfaces, inheritance, overriding, and composition to share behavior without making rigid class designs.

Use packages, imports, naming conventions, and project layout so larger Java programs stay navigable.

Handle String, StringBuilder, arrays, dates, times, formatting, and common utility classes from the standard library.

Store and process groups of values with List, Set, Map, Queue, iterators, and the tradeoffs between them.

Use type parameters, wildcards, bounds, and generic methods to write code that is flexible without giving up type safety.

Use checked and unchecked exceptions, try-catch-finally, try-with-resources, and custom exception types to handle failure clearly.

Read and write files with Path, Files, streams, encodings, buffering, and safe resource handling.

Write unit tests with JUnit, name test cases well, check edge cases, and use tests as a safety net while changing code.

Track changes, create branches, review diffs, and recover from mistakes using Git in a Java project.

Build repeatable projects with Maven and Gradle, including source layout, tasks, plugins, and test runs.

Add libraries, read version numbers, resolve conflicts, and keep dependency trees from becoming confusing or unsafe.

Use lambdas, method references, streams, collectors, and Optional to write clear data-processing code in modern Java.

Use enums, records, sealed classes, and compact constructors to represent data and rules with less boilerplate.

Use modern switch expressions, pattern matching, and guarded cases to make branching code safer and easier to read.

Use annotations and reflection so frameworks can discover routes, tests, validation rules, database mappings, and dependency wiring.

Use the Java Platform Module System to declare module boundaries, control exported packages, and build stronger large applications.

See how the heap, stack, class loading, garbage collection, and object references affect memory use and program behavior.

Use threads, locks, synchronized blocks, concurrent collections, executors, futures, and the Java memory model to avoid race conditions.

Use virtual threads and structured concurrency to handle many blocking tasks with simpler code than traditional thread pools.

Use CompletableFuture, Flow, and reactive libraries when programs need non-blocking pipelines, backpressure, and event-driven work.

Use sockets and the built-in HTTP client to call services, send requests, handle responses, and deal with timeouts.

Turn Java objects into JSON and back with common libraries while handling dates, missing fields, validation, and version changes.

Use JDBC, connection pools, SQL queries, prepared statements, result sets, and transactions to connect Java code to relational databases.

Use JPA and Hibernate to map objects to tables, manage entity lifecycles, avoid lazy-loading surprises, and write practical queries.

Create HTTP endpoints, handle requests and responses, wire services together, and package a small API with Spring Boot.

Validate input, return useful error responses, document endpoints with OpenAPI, and keep API behavior predictable for clients.

Use authentication, authorization, password hashing, TLS, secrets, dependency updates, and secure defaults in Java applications.

Test databases, web endpoints, message flows, and external integrations with mocks, fakes, contract tests, and Testcontainers.

Use logs, metrics, traces, correlation IDs, and health checks so Java services can be diagnosed after deployment.

Profile CPU, memory, garbage collection, startup time, and database calls before choosing fixes that actually improve performance.

Call native libraries, use JNI and the Foreign Function and Memory API, and judge when native access is worth the extra risk.

Build native executables with GraalVM, handle reflection configuration, compare startup and memory gains, and know the limits.

Build container images, choose JVM container settings, pass configuration safely, and run Java apps consistently across machines.

Use cloud databases, object storage, queues, secrets, identity, and managed services from Java without hard-coding infrastructure details.

Deploy Java services with Kubernetes manifests, probes, resource limits, config maps, secrets, rolling updates, and scaling rules.

Run Java workloads as serverless functions or edge services, with attention to cold starts, packaging, state, and cost.

Automate builds, tests, security checks, packaging, and deployment through a CI/CD pipeline for Java projects.

Check dependency provenance, vulnerability reports, build reproducibility, signing, SBOMs, and repository hygiene for Java projects.

Use AI coding assistants to generate Java code, tests, refactors, and explanations while checking correctness, security, licenses, and style.

Work through a real feature from issue to design, branch, implementation, tests, review, build, deployment, monitoring, and follow-up fix.

Read older Java code, upgrade language versions, replace risky libraries, add tests around behavior, and refactor without breaking users.

Compare backend, Android, data, platform, tooling, and enterprise Java roles; plan portfolio projects, certifications, interviews, open-source paths, and ways to stay current with JEPs and LTS releases.