🎤 टॉप 81 Interview Questions
ये सबसे common Java interview questions हैं — tap करके answer खोलो।
HyperText Markup Language — EK MARKUP LANGUAGE (PROGRAMMING language NAHI) JO WEB PAGES ki STRUCTURE/CONTENT DEFINE karti hai — HEADINGS, PARAGRAPHS, LINKS, IMAGES, SAB HTML ELEMENTS SE BANTE hain.
Tag, ANGLE BRACKETS mein LIKHA JAATA hai (jaise <p>). Element, OPENING TAG + CONTENT + CLOSING TAG, POORA MILAKE BANTA hai (jaise <p>Hello</p>).
EXTRA INFORMATION, TAG ke ANDAR, NAME="VALUE" FORMAT mein — jaise <img src="pic.jpg" alt="Description"> — src aur alt ATTRIBUTES hain.
Browser ko BATATA hai KI YE DOCUMENT, HTML5 STANDARDS FOLLOW karta hai — ISKE BINA, Browser "QUIRKS MODE" mein CHALA JA SAKTA hai, JAHA OLD, INCONSISTENT RENDERING RULES APPLY hote hain.
<head> mein METADATA hota hai (title, CSS links, meta tags) — DIRECTLY VISIBLE NAHI hota. <body> mein ACTUAL, VISIBLE CONTENT hota hai (text, images, buttons).
Block-level elements (jaise <div>, <p>) EK NAYI LINE SE SHURU hote hain, POORI WIDTH LETE hain. Inline elements (jaise <span>, <a>) SIRF UTNI WIDTH LETE hain JITNI CONTENT ki ZAROORAT hai, LINE ke BEECH mein FIT ho jaate hain.
<div> EK BLOCK-LEVEL, GENERIC CONTAINER hai (LARGE SECTIONS GROUP karne ke liye). <span> EK INLINE, GENERIC CONTAINER hai (CHHOTE, TEXT ke ANDAR ke PORTIONS ko STYLE karne ke liye).
<b> SIRF VISUALLY BOLD karta hai (KOI SEMANTIC MEANING NAHI). <strong> "IMPORTANCE" SIGNAL karta hai (SCREEN READERS, SEO ke liye MEANINGFUL) — BEST PRACTICE, SEMANTIC tags PREFER karna hai.
<br> EK SINGLE LINE BREAK INSERT karta hai (SAME PARAGRAPH ke ANDAR). <p> EK POORA NAYA PARAGRAPH SHURU karta hai (EXTRA SPACING ke SAATH, SEMANTICALLY SEPARATE BLOCK).
USER INPUT COLLECT karne ke liye — <input>, <textarea>, <select> jaise FORM CONTROLS ko GROUP karta hai, aur SUBMIT hone PAR, DATA ko SERVER PAR BHEJTA hai (action ATTRIBUTE mein SPECIFIED URL PAR).
GET, DATA ko URL mein APPEND karta hai (VISIBLE, BOOKMARK-ABLE, LIMITED SIZE — SEARCH ke liye ACHHA). POST, DATA ko REQUEST BODY mein BHEJTA hai (HIDDEN, LARGER DATA, SENSITIVE INFO ke liye BETTER).
Input FIELD ko, EK READABLE TEXT DESCRIPTION SE, ASSOCIATE karta hai (for ATTRIBUTE SE) — ACCESSIBILITY ke liye CRITICAL (SCREEN READERS), aur LABEL PAR CLICK karne SE, INPUT bhi FOCUS ho jaata hai.
Browser ko BATATA hai KI YE FIELD, FORM SUBMIT hone SE PEHLE, KHAALI NAHI CHHODA JA SAKTA — BUILT-IN, CLIENT-SIDE VALIDATION PROVIDE karta hai, BINA JAVASCRIPT ke.
type="email", Browser ko VALIDATION karne DETA hai (VALID EMAIL FORMAT hai YA NAHI) — MOBILE devices PAR, SPECIALIZED KEYBOARD bhi DIKHA sakta hai (@ symbol EASILY ACCESSIBLE).
<table> (CONTAINER), <tr> (TABLE ROW), <td> (TABLE DATA/CELL), <th> (TABLE HEADER CELL) — SAB MIL KE, EK GRID-LIKE STRUCTURE BANATE hain.
Table KO, LOGICALLY, HEADER (thead), BODY (tbody), aur FOOTER (tfoot) SECTIONS mein DIVIDE karte hain — SEMANTIC CLARITY, aur STYLING/SCRIPTING ke liye ORGANIZATION DETE hain.
colspan, EK CELL ko, MULTIPLE COLUMNS ke BARABAR, HORIZONTALLY, MERGE karta hai. rowspan, EK CELL ko, MULTIPLE ROWS ke BARABAR, VERTICALLY, MERGE karta hai.
TAGS JO, APNE NAAM SE HI, APNI CONTENT ka MEANING/PURPOSE BATATE hain — jaise <header>, <nav>, <article>, <footer> — SIRF <div> use karne se BEHTAR hai, SEO aur ACCESSIBILITY ke liye.
<article>, EK INDEPENDENT, SELF-CONTAINED CONTENT PIECE hai (jaise EK BLOG POST, JO ALAG SE bhi DISTRIBUTE ho sakta hai). <section>, EK THEMATIC GROUPING hai (jaise EK PAGE ka "About" SECTION).
MAJOR NAVIGATION LINKS ko WRAP karne ke liye (jaise MAIN MENU, BREADCRUMBS) — SAARE LINKS ko <nav> mein DAALNA ZAROORI NAHI, SIRF PRIMARY, SITE-WIDE NAVIGATION BLOCKS ke liye.
AGAR IMAGE LOAD NA ho (YA SCREEN READER USE ho rahi ho), alt TEXT, IMAGE ka ALTERNATIVE, TEXTUAL DESCRIPTION DETA hai — ACCESSIBILITY aur SEO, DONO ke liye ESSENTIAL.
NATIVE, BUILT-IN media PLAYBACK — controls ATTRIBUTE SE, PLAY/PAUSE/VOLUME BUTTONS AUTOMATICALLY MIL jaate hain, EXTERNAL PLUGINS (jaise FLASH) ki zaroorat NAHI.
DIFFERENT SCREEN SIZES/RESOLUTIONS ke liye, DIFFERENT IMAGE FILES SERVE karne DETA hai (RESPONSIVE IMAGES) — MOBILE PAR CHHOTI, LIGHTWEIGHT IMAGE, DESKTOP PAR BADI, HIGH-RES IMAGE.
PAGE KE BAARE MEIN METADATA PROVIDE karte hain (jo VISIBLE CONTENT NAHI hai) — jaise CHARACTER ENCODING, VIEWPORT SETTINGS, aur SEO ke liye page DESCRIPTION.
Browser ko BATATA hai KI PAGE ko, DEVICE ki ACTUAL SCREEN WIDTH ke HISAAB SE, RENDER karo — ISKE BINA, MOBILE PAR, PAGE "ZOOMED OUT", DESKTOP-SIZE PAR DIKHTA hai.
Browser TAB mein DIKHTA hai, aur SEARCH ENGINE RESULTS mein CLICKABLE HEADLINE ke ROOP mein bhi USE hota hai — SEO aur USER EXPERIENCE, DONO ke liye CRITICAL.
Accessible Rich Internet Applications — EXTRA ATTRIBUTES (jaise aria-label, aria-hidden) JO, SCREEN READERS ko, ELEMENTS ke PURPOSE/STATE ke BAARE mein, EXTRA INFORMATION DETE hain, SPECIALLY DYNAMIC/CUSTOM COMPONENTS ke liye.
SAB USERS, MOUSE USE NAHI kar sakte (MOTOR DISABILITIES, ya SIRF PREFERENCE) — SAARE INTERACTIVE ELEMENTS (LINKS, BUTTONS, FORM FIELDS), Tab KEY SE, LOGICALLY NAVIGATE-ABLE HONE CHAHIYE.
CUSTOM ATTRIBUTES, HTML ELEMENTS PAR, EXTRA DATA STORE karne ke liye — jaise <div data-user-id="42">JavaScript SE, dataset.userId SE, EASILY ACCESS ho sakte hain.
EK DUSRE HTML DOCUMENT ko, CURRENT PAGE ke ANDAR, EMBED karta hai — jaise YOUTUBE VIDEOS, GOOGLE MAPS, EXTERNAL WEBSITES ko, EK PAGE ke ANDAR DIKHANE ke liye USE hota hai.
SEMANTIC TAGS (header, footer, article, section), NATIVE MEDIA SUPPORT (video, audio), NEW INPUT TYPES (email, date), aur LOCAL STORAGE — WEB DEVELOPMENT ko MODERN, RICHER bana diya.
SPECIAL CHARACTERS (jaise <, >, &) JO, HTML SYNTAX mein, SPECIAL MEANING RAKHTE hain, unhe LITERALLY DISPLAY karne ke liye — jaise < se "<" DIKHTA hai, BINA HTML TAG SAMAJHE JAANE ke.
<!-- comment text --> SYNTAX SE — BROWSER SE HIDDEN rehte hain, LEKIN SOURCE CODE mein VISIBLE hote hain, DOCUMENTATION/NOTES ke liye USEFUL.
<ul> UNORDERED (BULLETED) LIST hai. <ol> ORDERED (NUMBERED) LIST hai. <li> HAR EK, INDIVIDUAL LIST ITEM hai — DONO LIST TYPES ke ANDAR USE hota hai.
<blockquote>, EK LAMBI, MULTI-LINE QUOTATION ke liye (BLOCK-LEVEL, EXTRA INDENTATION KE SAATH). <q>, EK CHHOTI, INLINE QUOTATION ke liye (AUTOMATICALLY QUOTATION MARKS ADD hote hain).
<select>, EK DROPDOWN MENU CONTAINER hai. <option>, HAR INDIVIDUAL CHOICE hai, DROPDOWN ke ANDAR — USER, EK (YA MULTIPLE, multiple ATTRIBUTE SE) OPTION(S) SELECT kar sakta hai.
<textarea>, MULTI-LINE TEXT INPUT ke liye hai (jaise COMMENTS, LONG MESSAGES). <input type="text">, SINGLE-LINE, SHORT TEXT ke liye hai (jaise NAAM, EMAIL).
placeholder, EK LIGHT-COLORED, HINT TEXT DIKHATA hai (JAB FIELD KHAALI ho) — TYPING SHURU hote hi GAYAB ho jaata hai. value, ACTUAL, SUBMITTED DATA hai (INITIAL/CURRENT VALUE).
CSS (overflow-x: auto WRAPPER se HORIZONTAL SCROLL, YA MEDIA QUERIES SE LAYOUT CHANGE karके) — HTML KHUD, RESPONSIVENESS PROVIDE NAHI karta, CSS ki ZAROORAT PADTI hai.
<header>, PAGE (YA SECTION) KA INTRODUCTORY CONTENT (LOGO, NAVIGATION, HEADING) HAI. <footer>, PAGE (YA SECTION) KA CLOSING CONTENT (COPYRIGHT, CONTACT INFO, LINKS) HAI.
MAIN CONTENT SE, TANGENTIALLY RELATED, SIDE CONTENT ke liye — jaise SIDEBAR, PULL QUOTES, RELATED LINKS — MAIN CONTENT ka DIRECT HISSA NAHI, LEKIN SUPPLEMENTARY.
PAGE ka PRIMARY, UNIQUE CONTENT WRAP karta hai (HEADER, FOOTER, NAV EXCLUDE karके) — EK PAGE mein SIRF EK <main> element HONA CHAHIYE, SCREEN READERS ko "MAIN CONTENT" tak SEEDHA JUMP karne DETA hai.
MULTIPLE FILE FORMATS PROVIDE karne ke liye (jaise MP4, WebM) — Browser, JO FORMAT SUPPORT karta hai, WOHI AUTOMATICALLY CHOOSE kar leta hai — CROSS-BROWSER COMPATIBILITY ke liye.
loading="lazy" ATTRIBUTE, <img> TAG PAR — IMAGE, TAB tak LOAD NAHI hoती, JAB TAK USER, SCROLL karte-karte, USKE NAZDEEK NAHI POHONCH JAATA — PAGE LOAD SPEED IMPROVE hoती hai.
SPECIAL <meta> tags (og:title, og:image, etc.) JO CONTROL karte hain KI, SOCIAL MEDIA PAR SHARE karте waqt, PAGE KAISA PREVIEW DIKHEGA (title, image, description).
<link rel="canonical"> SE, SEARCH ENGINES ko BATAYA JAATA hai KI, AGAR SAME CONTENT, MULTIPLE URLs PAR ACCESSIBLE hai, TO "ORIGINAL" URL KAUN SI hai — DUPLICATE CONTENT SEO ISSUES AVOID karta hai.
TEXT aur BACKGROUND COLOR ke BEECH, ENOUGH CONTRAST HONA CHAHIYE, taaki LOW-VISION USERS bhi CONTENT PADH sakein — WCAG STANDARDS, MINIMUM CONTRAST RATIOS SPECIFY karte hain.
HAR input, EK ASSOCIATED <label> (for ATTRIBUTE SE) RAKHNA CHAHIYE — BINA LABEL ke, SCREEN READER USER ko PATA NAHI CHALEGA, FIELD KIS CHEEZ KE LIYE hai.
CUSTOM, REUSABLE HTML ELEMENTS BANANE ka EK STANDARD — CUSTOM ELEMENTS, SHADOW DOM, aur HTML TEMPLATES, MIL KAR, FRAMEWORK-INDEPENDENT, ENCAPSULATED COMPONENTS ENABLE karte hain.
HTML CONTENT DEFINE karta hai JO, PAGE LOAD hote hi, IMMEDIATELY RENDER NAHI HOTA — JavaScript SE, BAAD MEIN, DYNAMICALLY CLONE/INSERT kiya ja sakta hai — REUSABLE MARKUP PATTERNS ke liye USEFUL.
HTML5, HTML ka LATEST, MODERN VERSION hai — NAYE SEMANTIC TAGS, MULTIMEDIA SUPPORT, aur APIs (LOCAL STORAGE, GEOLOCATION) ADD karta hai, JO PURANE HTML VERSIONS mein NAHI THE.
<!DOCTYPE html>, <html>, <head> (metadata), aur <body> (visible content) — YE FOUR PARTS, HAR HTML PAGE ki FOUNDATION hain.
Elements JINKI CLOSING TAG NAHI HOTI (jaise <br>, <img>, <input>) — YE, APNE AAP mein, COMPLETE hote hain, KOI CONTENT WRAP NAHI karte.
id, EK PAGE PAR, EK ELEMENT ke liye, UNIQUE hona CHAHIYE (SIRF EK BAAR USE). class, MULTIPLE ELEMENTS PAR, REPEAT ho sakti hai (SHARED STYLING/BEHAVIOR ke liye).
<em>, "EMPHASIS" (IMPORTANCE) SIGNAL karta hai (SEMANTIC). <i>, SIRF VISUALLY ITALIC karta hai (KOI SEMANTIC MEANING NAHI) — jaise EK TECHNICAL TERM ko ITALICIZE karna.
<sup>, TEXT ko SUPERSCRIPT (UPAR) DIKHATA hai (jaise x²). <sub>, TEXT ko SUBSCRIPT (NEECHE) DIKHATA hai (jaise H₂O).
EK THEMATIC BREAK (HORIZONTAL LINE) INSERT karta hai — CONTENT ke DO SECTIONS ke BEECH, EK VISUAL/SEMANTIC SEPARATION SHOW karne ke liye.
<fieldset>, RELATED FORM CONTROLS ko, EK VISUAL BOX mein, GROUP karta hai. <legend>, US GROUP ka, EK CAPTION/TITLE PROVIDE karta hai.
Radio buttons (SAME name ATTRIBUTE ke SAATH), SIRF EK OPTION SELECT hone deते hain (MUTUALLY EXCLUSIVE). Checkboxes, MULTIPLE OPTIONS, EK SAATH, SELECT hone dete hain.
disabled, FIELD ko COMPLETELY NON-INTERACTIVE bana deta hai (FORM SUBMIT mein bhi SHAAMIL NAHI hota). readonly, FIELD ko EDIT hone se ROKTA hai, LEKIN FORM SUBMIT mein VALUE SHAAMIL hoती hai.
required, pattern, min/max, type="email" jaise ATTRIBUTES SE, Browser AUTOMATICALLY VALIDATION karta hai, BINA JAVASCRIPT LIKHE — INVALID DATA PAR, SUBMIT BLOCK ho jaata hai.
TABLE ka EK TITLE/DESCRIPTION PROVIDE karta hai — TYPICALLY, TABLE ke UPAR DISPLAY hota hai, aur SCREEN READERS ke liye, TABLE ka PURPOSE CLEAR karta hai.
BATATA hai KI YE HEADER, EK ROW ke liye hai YA COLUMN ke liye (scope="row"/"col") — SCREEN READERS, ISKI HELP SE, HAR CELL ko, USKE CORRECT HEADER SE, ASSOCIATE kar paate hain.
<figure>, EK SELF-CONTAINED CONTENT (jaise IMAGE, DIAGRAM) WRAP karta hai. <figcaption>, USKA CAPTION/DESCRIPTION PROVIDE karta hai.
DATE/TIME ko, HUMAN-READABLE FORMAT mein DIKHATE hue, MACHINE-READABLE FORMAT bhi PROVIDE karta hai (datetime ATTRIBUTE SE) — SEARCH ENGINES, CALENDARS ke liye USEFUL.
Search ENGINES, SEMANTIC TAGS (header, article, nav) SE, PAGE ki STRUCTURE aur IMPORTANT CONTENT ko, BEHTAR SAMAJH paate hain — DIV-ONLY LAYOUTS se, RANKING/UNDERSTANDING POORER hoती hai.
EXTERNAL CONTENT (jaise PDFs, PLUGINS) ko, PAGE ke ANDAR, EMBED karte hain — MODERN WEB mein, <iframe> aur NATIVE HTML5 tags (video, audio) SE, LARGELY REPLACE ho chuke hain.
MULTIPLE IMAGE VERSIONS (DIFFERENT RESOLUTIONS) SPECIFY karne DETA hai — Browser, DEVICE ke SCREEN/RESOLUTION ke HISAAB SE, SABSE APPROPRIATE VERSION AUTOMATICALLY CHOOSE karta hai.
robots.txt, EK SEPARATE FILE hai, POORE SITE ke liye, CRAWLING RULES DEFINE karti hai. <meta name="robots">, EK SPECIFIC PAGE PAR, INDEXING/FOLLOWING BEHAVIOR CONTROL karta hai.
EK LOGICAL, NESTED STRUCTURE (h1 → h2 → h3) PROVIDE karta hai — SEARCH ENGINES aur SCREEN READERS, ISSE PAGE ki OUTLINE SAMAJHTE hain — LEVELS SKIP karna (h1 se DIRECT h4) BAD PRACTICE hai.
Web Content Accessibility Guidelines — INTERNATIONAL STANDARDS, JO DEFINE karte hain KI, WEB CONTENT, DISABILITIES WALE USERS ke liye, KAISE ACCESSIBLE BANAYA JAAYE.
VISUAL OUTLINE JO DIKHATA hai KI, KEYBOARD SE, CURRENTLY KAUN SA ELEMENT SELECTED hai — outline: none SE ISE REMOVE karna, KEYBOARD USERS ke liye, NAVIGATION IMPOSSIBLE bana deta hai.
EK HIDDEN (LEKIN KEYBOARD-FOCUS PAR VISIBLE) LINK, PAGE ke SABSE UPAR, JO USER ko, REPETITIVE NAVIGATION LINKS SKIP KARKE, DIRECTLY MAIN CONTENT PAR JAANE DETA hai.
EK ENCAPSULATED DOM TREE, EK ELEMENT ke ANDAR, JISKI STYLING/STRUCTURE, MAIN DOCUMENT SE ISOLATED rehti hai — Web Components ka EK CORE PART, STYLE CONFLICTS AVOID karta hai.
KISI BHI HTML ELEMENT ko, DIRECTLY, BROWSER mein, USER-EDITABLE bana deta hai (BINA <input>/<textarea> ke) — RICH TEXT EDITORS ISI PAR AKSAR BASED hote hain.
CHECK karna KI HTML CODE, W3C STANDARDS FOLLOW karta hai (PROPER NESTING, CLOSING TAGS) — INVALID HTML, DIFFERENT BROWSERS mein, INCONSISTENT RENDERING de sakta hai.
PEHLE, EK BASIC, FUNCTIONAL HTML PAGE BANAO (BINA CSS/JS ke bhi KAAM kare), PHIR CSS/JS SE, LAYER BY LAYER, ENHANCEMENTS ADD karo — SAB USERS/BROWSERS ke liye, EK BASELINE EXPERIENCE GUARANTEE karta hai.
<meta charset="UTF-8"> SE, Browser ko BATATA hai KI TEXT CHARACTERS ko, KAISE INTERPRET/DISPLAY karna hai — UTF-8, LAGBHAG SAARI LANGUAGES/SYMBOLS SUPPORT karta hai, MODERN STANDARD hai.
Elements, PROPERLY NESTED HONE CHAHIYE — jaise <b><i>text</i></b> CORRECT hai, LEKIN <b><i>text</b></i> INVALID hai (OVERLAPPING, IMPROPER CLOSING ORDER).
PAGE LOAD hote hi, US SPECIFIC FIELD ko, AUTOMATICALLY FOCUS kar deta hai (CURSOR WAHI BLINK karta hai) — USER, TURANT TYPING SHURU kar sakta hai, BINA MANUALLY CLICK kiye.
EK NATIVE, COLLAPSIBLE/EXPANDABLE CONTENT SECTION BANATE hain — SAMMARY (HEADING) PAR CLICK karne SE, DETAILS SHOW/HIDE hoते hain, BINA JAVASCRIPT LIKHE.