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A string is immutable, so every change creates a new string object, while StringBuilder is a mutable buffer that modifies its contents in place, making it much faster for repeated concatenation.
The JVM runs Java bytecode, the JRE is the JVM plus the standard libraries needed to run Java programs, and the JDK is the JRE plus the development tools such as the compiler (javac).
== compares primitives by value and objects by reference (whether they are the exact same object), while equals() compares the logical content of two objects when the class overrides it.
String is immutable, StringBuilder is a mutable and fast but not thread-safe buffer, and StringBuffer is a mutable buffer with synchronized methods that is thread-safe but slower.
final is a keyword that prevents reassigning a variable, overriding a method or extending a class; finally is a block that always runs after try/catch for cleanup; finalize() was a method called by the garbage collector and is now deprecated.
A list is mutable and can be changed after creation, while a tuple is immutable; tuples are slightly faster, use less memory and can be used as dictionary keys when their items are hashable.
== checks whether two objects have equal values, while is checks whether they are the exact same object in memory.
Git is a distributed version control system that tracks changes to files on your machine; GitHub is a hosting service for Git repositories that adds collaboration features such as pull requests, code review and CI.
git fetch downloads new commits from the remote without changing your working branch; git pull runs a fetch and then merges (or rebases) those commits into your current branch.
A virtual machine runs a full guest operating system on virtualised hardware, while a container shares the host鈥檚 kernel and isolates only the process, its filesystem and resources, which makes containers much lighter and faster to start.
An image is a read-only template made of layers that contains the application and its dependencies; a container is a running (or stopped) instance of an image with its own writable layer on top.
Unit tests check one small piece of code in isolation, integration tests check that several pieces work together (for example code plus a real database), and end-to-end tests drive the whole application the way a user would.
Normalise the string (lower case, remove non-alphanumeric characters), then compare characters from both ends moving inward with two pointers. This is O(n) time and O(1) extra space beyond the normalised copy.
Give a 60-90 second summary in three parts: what you do now, one or two achievements that show your strengths, and why this role is the logical next step.
Connect two or three of your strongest, provable skills directly to the needs in the job description, give a short piece of evidence for each, and show genuine interest in the team鈥檚 work.
Give specific evidence of deliberate learning through projects, feedback, reading, experimentation or mentoring rather than listing technologies.
Connect something specific about the company, product, engineering challenges or team to your own experience and career goals.
Hooks are functions such as useState and useEffect that let function components use state, lifecycle behaviour and other React features; they must be called at the top level of a component or custom hook, never inside loops, conditions or nested functions.
Keys give each list item a stable identity so React can match items between renders and correctly add, remove or reorder them without recreating or mixing up their state.
em is relative to the parent font size, rem is relative to the root font size, % is relative to the parent鈥檚 relevant size, and vh/vw are 1% of the viewport height or width.