wait(), notify() & notifyAll()
Duration: 21 min
This video lesson is available to enrolled students.
Inside: a video lesson and guided study material.
Module outline
- Paper 1 | Reasoning Test: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Puzzle Solving (Puzzles), Venn Diagram, Analogy, Ranking, Order and Sequence, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Cubes & Dices, Analytical Reasoning (Counting Figures Reasoning), Calendar, Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Algebra, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Speed, Time and Distance, Traverse Surveying, Ratio and Proportion, Time and Work, Mensuration, Permutations and Combinations, Clocks and Calendars, Data Interpretation, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations, Data Sufficiency
- Paper 1 | Numerical Analysis: Number System, HCF LCM, Percentage, Ratio and Proportion (Ratios), Average, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Data Interpretation, Mental Ability, Arithmetic, Logarithm, Profit and Loss, Simple Interest and Compound Interest, Speed Time and Distance, Mixture and Alligation, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Graph Theory, Combinatorics
- Paper 1 | General Knowledge: State Wise GK, History, Geography, GK- Current Affairs, Static General Knowledge, Polity, Indian Economy
- Paper 1 | DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Transaction Management, Concurrency Control, Relational Calculus, Database Security & Authorization, Database Recovery
- Paper 1 | Data Communication & Network: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Network Security, Security in Mobile and Wireless Computing, Input Output Organisation, File Management, Hardware Basics, Terms & Abbreviations, Protocols & Services, Network Access Technologies, Cyber Safety and Security, Basics of COA
- Paper 2 | System Analysis & Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Security, Risk Management & Maintenance, extras
- Paper 2 | Programming Language (Java): Java Fundamentals, OOPS with Java, Array, String, IO & References, Generic & Collections, Multithreading, Java, Miscellaneous, Control Flow, OOPS with C++, Stack, C Fundamentals, Arrays & Pointers, Object Oriented Technology, Control Flow & Looping, Introduction to Python
AI summary & chapters
AI Summary
An AI-generated summary of this video lecture.
This lecture introduces Java's wait(), notify(), and notifyAll() methods for inter-thread communication. The instructor explains that these final void methods are defined in the Object class and must be invoked inside synchronized blocks or methods. wait() causes the current thread to release its monitor lock and enter a waiting state until another thread calls notify() or notifyAll(). Three forms of wait() are shown: wait(), wait(long timeout), and wait(long timeout, int nanos). notify() wakes one waiting thread on the same object's monitor, while notifyAll() makes all waiting threads eligible to continue. A comparison table distinguishes the methods by how many threads are awakened. The lesson then moves to a Java code example in an IDE, where synchronized(obj) blocks contain obj.wait(), notify(), and notifyAll() calls. The console output shows messages such as 'Thread 1 is waiting', 'notify() called', and 'notifyAll() called'. The instructor annotates the code with red circles, arrows, and handwritten notes linking t1.start() and t2.start() to the wait mechanism. The final slide recaps the method syntax and behavior.
Chapters
0:00 – 2:00 00:00-02:00
The video opens with the slide titled 'wait(), notify() and notifyAll() Methods'. It lists the three methods, shows syntax such as 'final void wait() throws InterruptedException' and 'final void notify()', and presents a comparison table. The instructor begins a hand-drawn diagram with Main pointing to T1 and T2, an object box labeled 'obj' and 'Syn()', and a flow toward Run, Unlock, and wait T1.
2:00 – 5:00 02:00-05:00
The instructor explains that wait() releases the monitor lock while waiting for another thread to call notify() or notifyAll(). The slide lists the three wait forms: 'wait()', 'wait(long timeout)', and 'wait(long timeout, int nanos)'. A red box highlights the 'wait T1' portion of the diagram. The instructor circles wait() in the title, then adds notify() and notifyAll(), expanding the diagram to show multiple threads T1 and T2 in waiting states.
5:00 – 10:00 05:00-10:00
The instructor emphasizes that these methods are defined in the 'Object class' and used within 'synchronized methods or blocks', circling these terms in red. Arrows illustrate the relationship between wait() and notify()/notifyAll(). The slide states that 'wait() method causes the current thread to wait until another thread calls notify()' and that 'notify() method wakes up one thread waiting on the same object's monitor'.
10:00 – 15:00 10:00-15:00
The lesson introduces notifyAll(), whose syntax is 'final void notifyAll()' and which wakes all threads waiting on the same object's monitor. A comparison table contrasts wait, notify, and notifyAll by thread-state outcomes. The instructor highlights 'all threads' versus 'one thread', then transitions to a Java code example in an IDE, with program output showing threads waiting and awakening.
15:00 – 20:00 15:00-20:00
The instructor annotates the code example, highlighting synchronized blocks containing notify() and notifyAll(). Red circles mark obj.wait(), and handwritten margin notes connect t1.start() and t2.start() to a 'wait -> T1' note. The output console displays the sequence: 'Thread 1 is waiting', then 'notify() called' and 'notifyAll() called'. The view switches back to the text slide summarizing method syntax and behavior.
20:00 – 20:53 20:00-20:53
The final segment recaps the theoretical overview. The slide again lists 'final void wait() throws InterruptedException', the three wait forms, and states that notify() wakes one thread. The instructor reinforces that these Object-class methods require synchronized context for correct monitor-lock release and re-acquisition.
The lecture progresses from definitions to visual diagrams, then to a comparison table and finally a runnable code demonstration. Central ideas are: (1) wait(), notify(), and notifyAll() belong to the Object class, not Thread; (2) they must be called inside synchronized blocks or methods because wait() releases the object's monitor lock; (3) wait() has three forms, including timed variants that throw InterruptedException; (4) notify() resumes one waiting thread nondeterministically, while notifyAll() makes all waiting threads eligible; and (5) the code example ties thread start commands to synchronized(obj) blocks where obj.wait() suspends execution until notify/notifyAll is invoked. The console output provides concrete evidence of the waiting and awakening sequence.