How to optimize java code

How do I optimize my code?

Try to avoid implementing cheap tricks to make your code run faster.

  1. Optimize your Code using Appropriate Algorithm. …
  2. Optimize Your Code for Memory. …
  3. printf and scanf Vs cout and cin. …
  4. Using Operators. …
  5. if Condition Optimization. …
  6. Problems with Functions. …
  7. Optimizing Loops. …
  8. Data Structure Optimization.

How can I speed up my Java code?

Here are the top 10 easy performance optimisations in Java:

  1. Use StringBuilder. This should be your default in almost all Java code. …
  2. Avoid regular expressions. …
  3. Do not use iterator() …
  4. Don’t call that method. …
  5. Use primitives and the stack. …
  6. Avoid recursion. …
  7. Use entrySet() …
  8. Use EnumSet or EnumMap.

How do you optimize a loop in Java?

If we decrease the number of instructions in an inner loop then the running time of a program may be improved even if we increase the amount of code outside that loop. For loop optimization the following three techniques are important: Code motion.

Example:

  1. while (i<10)
  2. {
  3. j= 3 * i+1;
  4. a[j]=a[j]-2;
  5. i=i+2;
  6. }

How do I optimize my C++ code?

Summary of Strategies for Optimizing C++ Code

  1. Use a Better Compiler, Use Your Compiler Better. C++ compilers are complex software artifacts. …
  2. Use Better Algorithms. …
  3. Use Better Libraries. …
  4. Reduce Memory Allocation and Copying. …
  5. Remove Computation. …
  6. Use Better Data Structures. …
  7. Increase Concurrency. …
  8. Optimize Memory Management.

What are the types of optimization techniques?

Main Menu

  • Continuous Optimization.
  • Bound Constrained Optimization.
  • Constrained Optimization.
  • Derivative-Free Optimization.
  • Discrete Optimization.
  • Global Optimization.
  • Linear Programming.
  • Nondifferentiable Optimization.
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How do I reduce the size of a code?

7 Answers

  1. Use generation functions instead of data tables where possible.
  2. Disable inline functions.
  3. Turn frequently used macros into functions.
  4. Reduce resolution for variables larger than the native machine size (ie, 8 bit micro, try to get rid of 16 and 32 bit variables – doubles and quadruples some code sequences)

Is Java Instanceof expensive?

instanceof is probably going to be more costly than a simple equals in most real world implementations (that is, the ones where instanceof is really needed, and you can’t just solve it by overriding a common method, like every beginner textbook as well as Demian above suggest).

Which is the fastest collection in Java?

Performing the fastest search – which collection should i use?

  • If you need fast access to elements using index, ArrayList should be choice.
  • If you need fast access to elements using a key, use HashMap.
  • If you need fast add and removal of elements, use LinkedList (but it has a very poor seeking performance).

19 мая 2015 г.

What is JVM tuning?

JVM tuning mainly involves optimizing the garbage collector for better collection performance so that applications running on VMs can have a larger throughput while using less memory and experiencing lower latency.

How do you optimize a loop?

Conclusion

  1. Rule number one: only optimize when there is a proven speed bottleneck. …
  2. Small is beautiful. …
  3. Use intrinsic operations. …
  4. Avoid calling functions written in Python in your inner loop. …
  5. Local variables are faster than globals; if you use a global constant in a loop, copy it to a local variable before the loop.
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What is Java performance tuning?

Following are few of the techniques specific to java performance tuning. … Use StringBuilder to concatenate Strings if your code area is thread-safe. Use + operator to concatenate strings if it is in single statement. Use primitives as much as possible instead of wrapper classes.

How do you optimize a nested loop in Java?

The rule is this: when writing nested loops make sure that the variables that change the most are in the most inner loop and those which change the least — in the most outer loop. This significantly reduces the number of jumps if the number of loops is big.

Which is faster C or C++?

C vs C++: Speed

C++ is an enhancement of the older C programming language. Because C++ supports object orientation and features like Polymorphism, Abstract Data Types, and Encapsulation, it tends to be faster than C.

Which loop is faster in C++?

The best loop is no loop at all ( search loop unrolling ). If you want to do something several times and very fast then consider doing it in parallel using multiple cores or even using SSE extended assembler instructions.

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