1. Java File Cursor stackoverflow.comIs there some library for using some sort of cursor over a file? I have to read big files, but can't afford to read them all at once into memory. I'm ... |
2. Is there a workaround for Java's poor performance on walking huge directories? stackoverflow.comI am trying to process files one at a time that are stored over a network. Reading the files is fast due to buffering is not the issue. The ... |
3. Java Object Serialization Performance tips stackoverflow.comI must serialize a huge tree of objects (7,000) into disk. Originally we kept this tree in a database with Kodo, but it would make thousands upon thousands of Queries ... |
4. What is the fastest way to read a large number of small files into memory? stackoverflow.comI need to read ~50 files on every server start and place each text file's representation into memory. Each text file will have its own string (which is the best type ... |
5. Counting the number of files in a directory using Java stackoverflow.comHow do I count the number of files in a directory using Java ? For simplicity, lets assume that the directory doesn't have any sub-directories. I know the standard method of : |
6. Most efficient idiom to read one integer only from a file? stackoverflow.comIn trying to resolve Facebook's Puzzle "Hoppity Hop", http://www.facebook.com/careers/puzzles.php?puzzle_id=7, I'm reading one integer only from a file. I'm wondering if this is the most efficient mechanism to do this? |
7. How to retrieve a list of directories QUICKLY in Java? stackoverflow.comSuppose a very simple program that lists out all the subdirectories name of a given directory. Sound simple enough? Except the only way to list all subdirectories in Java is to ... |
8. Why does reading a file into memory takes 4x the memory in Java? stackoverflow.comI have the following code which reads in the follow file, append a \r\n to the end of each line and puts the result in a string buffer: |
9. Poor performance by overriding Java class? stackoverflow.comI have the following class subclass of FilterInputStream with only one method overrided. However the performance of this class is so poor. It performs at 1/10 the speed of its superclass. ... |
10. What are the issues with non-static inner classes and serialization in Java stackoverflow.comThis morning my boss and I had a long and ultimately fruitless discussion about this, in the context of trying to diagnose performance problems with a web application. We didn't ... |
11. File copying in Java stackoverflow.comWhat is a better option (in terms of performance): copying a file using fileinputstream and fileoutputstream or running a OS specific command copy command from Java? |
12. Java does not have a listDirectories/listFiles method, any native library? stackoverflow.comPossible Duplicate:Java does not have a listDirectories/listFiles method, in order to find out your ... |
13. Read large amount of data from file in Java stackoverflow.comI've got text file that contains |
14. How to pass a file (read from Java) most effectively to a native method? stackoverflow.comI have approx. 30000 files (1MB each) which I want to put into a native method, which requires just an byte array and the size of it as arguments. I looked through ... |
15. Is Java serialization a tool to shrink the memory footprint? stackoverflow.comdoes serialization in Java always have to shrink the memory that is used to hold an object structure? Or is it likely that serialization will have higher costs? In other words: Is ... |
16. read files from directory and filter files from Java stackoverflow.comThe following codes goes through all directories and sub-directories and outputs just .java files; |
17. java file move high performance stackoverflow.comI am writing a media transcoding server in which I would need to move files in the filesystem and till now I am in the dilemma of whether using java renameTo ... |
18. is using import some.directory.* worse for performance? stackoverflow.comWhat is better for performance using |
19. Performance difference between Serializable and Externalizable (Java) stackoverflow.comI am working in a highly distributed environment. A lot of network access and a lot of db access. I have some classes that are send over and over the network , ... |
20. Java NIO vs DotNet IO Performance stackoverflow.comDoes anyone know what the performance difference is between Java NIO vs DotNet IO performance. Reading this question, it seems that standard Java-IO and DotNet-IO have very similar IO performance. What is ... |
21. Most efficient way to read files in Java? stackoverflow.comAs most other people, I deal with file I/O a lot and I wanted to make sure that I wasn't losing time on reading the file. I currently know of FileReader() ... |
22. Speeding up java deep copy operations stackoverflow.comWe have implemented a general purpose deep copy mechanism using serialization. |
23. Java File access - Performance considerations stackoverflow.comAll,
Considering my earlier query Stackoverflow-Post, here is what I am currently doing. This is a kind of flowchart:
1 > Add record to file: |
24. NTFS directory has 100K entries. How much performance boost if spread over 100 subdirectories? stackoverflow.comContext We have a homegrown filesystem-backed caching library. We currently have performance problems with one installation due to large number of entries (e.g. up to 100,000). The problem: we store all fs ... |
25. Speeding up OpenNLP's POSTagging when using it for several texts stackoverflow.comI'm currently working on a keyphrase extraction tool, which should provide tag suggestions for texts or documents on a website. As I am following the method proposed in this paper: |
26. Question on Java IO Performance tuning stackoverflow.comI am trying to optimize a web based application that does a lot of writing to the stream. The code is something like this --- |
27. what's the fastest way to scan a very large file in java? stackoverflow.comImagine I have a very large text file. Performance really matters. All I want to do is to scan it to look for a certain string. Maybe I want to count how many ... |
28. What would be "faster" when dealing with input and output? stackoverflow.comA simple program asking for user input could use datainputstream or scanner. Which would be faster? Datainputstream is binary so it may be faster? Is it in opinion? I'm just curious ... |
29. temp files in memory in java program stackoverflow.comIs there a way to force the temporary files created in a java program in memory? Since I use several large xml file, I would have advantages in this way? Should ... |
30. Netty performance stackoverflow.comIs there any real difference to the performance when you use Netty and if you don't use it in an application with tens of thousand of connections? |
31. Advantages of Java NIO in blocking mode versus traditional I/O? stackoverflow.comI have pretty much already decided not to use asynchronous, non-blocking Java NIO. The complexity versus benefit is very questionable in general, and I think it's not worth it in this ... |
32. Does compression increase performance? stackoverflow.comI'm using java and have many pictures to load from the hard drive. Generally, is it faster to use highly compressed pictures (that probably take long to decompress) or not compressed pictures ... |
33. Why do I get java.lang.OutOfMemoryError given the size of my file? stackoverflow.comI'm parsing a 328kb text file and storing the content in a java List. This is the command line (I'm supposed to use 1GB ram given the parameters). |
34. Java: Efficient way to scan a folder for a particular file stackoverflow.comI am contacting an external services with my Java app. The flow is as follow: ->I generate an XML file, and put it in an folder, then the service processes the ... |
35. Java Ant Performance when deleting directory stackoverflow.comHello fellow stackoverflowers, Most Ant build files I've seen online involve a "clean" target that always removes a directory using deltree and recreates that directory, where all the binaries will be outputted ... |
36. Faster way to read file stackoverflow.comI'm working on a program that has about 400 input files and about 40 output files. It's simple: it reads each input file and it generates a new file with but much ... |
37. Which xml serialization library is performance oriented? stackoverflow.comWhat is the best XML serialization library for Java if performance is the deciding factor? Salient Points of application
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38. java: need to increase performance of checksum calculation stackoverflow.comI'm using the following function to calculate checksums on files: |
39. What would be the fastest way to read integers from a file in Java? stackoverflow.comI have a file of integers arranged like this: |
40. Storing lots of small files: archive vs. filesystem stackoverflow.comI am creating an application that requires a lot of image thumbnails (~3000, 5-25KB). Because speed is essential I plan on loading these images into memory when the application starts. At ... |
41. OutOfMemoryError - can I dump data into file instead of memory? stackoverflow.comI'm using an API that provides a method like |
42. Will using longs instead of ints benefit in 64bit java stackoverflow.comIn a 64 bit VM, will using longs instead of ints do any better in terms of performance given that longs are 64 bits in java and hence pulling and processing ... |
43. Optimising file download stackoverflow.comSo I've got the following method for downloading files from Amazon S3 and for now it is working but I anticipated that in the future I'll have to deal with considerably ... |
44. Faster output via standard out in Java? stackoverflow.comIn an online judge programming contest problem I am required to output up to 50,000 lines in under 1 second via standard out (in addition to reading in up to 200,000 ... |
45. Sensible buffer size when downloading files in Java stackoverflow.comWhat is the sensible buffer size to use when transferring (irrespective of UP/DOWN) large files (3-4 gigs) with Java? |
46. Apache Camel File Output Component Performance slow - Java stackoverflow.comI'm using Camel to write a number of strings (100,000s) to set of text files. The below code shows my Camel route: |
47. NIO Performance Improvement compared to traditional IO in Java stackoverflow.comI have seen many articles/blogs saying that Java NIO is a better solution compared to traditional Java IO. But today one of my co-worker showed me this blog http://mailinator.blogspot.com/2008/02/kill-myth-please-nio-is-not-faster-than.html. I ... |
48. How can I measure file access performance (and volume) of a (Java) application stackoverflow.comGiven an application, how can I measure
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49. How can I read a certain amount of Bytes into a Buffer? stackoverflow.comThe following problem: I have a large textfile with each line containing 13 bytes. I do not want to read the file line by line in the common way using InputStream. ... |
50. Performance with File Output coderanch.comHi - I was wondering if anyone had any comments on performance issues related to writing data to a file. Currenctly, I'm performing the task like this: File f = new File("test.txt"); File Writer fs = new FileWriter(f); fw.write("This is a test"); I would like to hear comments about whether or not this is good from a perfomance standpoint or is ... |
51. Object serialization performance coderanch.comAn interesting question came up today: all other things being equal, is there a performance difference between writing a serialized object to a file and writing that object's data to a file? The object in question is a StringBuffer. I would tend to think that just writing the data to the file would be quicker, but that's a guess. Any thoughts? ... |
52. File size and Performance coderanch.comIt depends on your program. Just opening a file (by creating a FileInputStream for example) does not take up a huge amount of memory and the memory usage is not dependent on how large the file is. If you write a program that loads the whole contents of the file into memory, then yes, your program will need a lot of ... |
53. StringBuffer performance coderanch.comI have a large text processing application, and for once I am worried about java performance. Can someone help me evaluate these two approaches to meet the principle: Reuse; do not destroy and re construct in a loop. Which scenario improves performance the most, and why? Here is a terse example: StringBuffer sb = new StringBuffer(); //... While (loopIsNotDone) { //... ... |
54. Testing serialization performance coderanch.comI got this code from an article on javaworld. The original author used it to test deep-copying via serialization. Another article used the code to test serialization performance (http://www.javaworld.com/jw-09-2001/jw-0907-rmi.html ; the first bullet under Resources) Since I don't know too much about serialization, does this code look like a good performance tester for serialization? I'm considering making some of my classes ... |
55. Setting serialVerionUID for performance coderanch.com |
57. IO Performance coderanch.comDear Sir, I am using BufferedOutptStream class to write byte array to a file. Is there any other way to write to the file in a more effecient way in java . i have my own class called VFSIOService which has the methods addFile and copyFile which are responsible for writing and copying. This class is called by a stateless session ... |
58. nio performance issue coderanch.comDear Sir, I am doing I/O in my project for which I have decided to choose either nio or java.io for file writing and reading . I thought to choose nio because it uses direct memory and gives good performance . I was comparing nio with java.io for writing and reading a file size of 3mb . I was calculating the ... |
59. NIO and performance question coderanch.compackage org.jemos.nio; import java.nio.Buffer; import java.nio.ByteBuffer; import java.nio.ByteOrder; public class RemainingTest { public static void main(String[] args) { new RemainingTest().doTest(); } private void doTest(){ ByteBuffer buf = ByteBuffer.allocate(5).order(ByteOrder.BIG_ENDIAN); buf.put((byte)'H').put((byte)'e').put((byte)'l').put((byte)'l').put((byte)'o'); buf.flip(); printByteBuffer(buf); printStats(buf); } private void printStats(Buffer buf){ System.out.println("Position:\t" + buf.position()); System.out.println("Limit:\t" + buf.limit()); } private void printByteBuffer(ByteBuffer buf){ while(buf.hasRemaining()){ System.out.print((char)buf.get()); } System.out.println(""); } } |
60. SequenceInputStream performance coderanch.comI'm using a SequenceInputStream to read multiple files and merge them together into one file. This is way slow. I'm guessing due to buffering. How do I properly buffer with a SequenceInputStream. My code is below. Note that I'm buffering output, but not input. I tried using s.read(byte[] b, int off, int len) but my output was wacked, I apparantly did ... |
61. Any Performance Optimization Tips for using NIO coderanch.comIn most cases it's as Joe says. On big exception is - if you want to copy bytes to or from a file - use FileChannel's transferFrom() or transferTo() methods. They are faster (typically) and easier to use than doing the same thing with streams. Which is unusual - typically the NIO stuff is harder to use, and only sometimes is ... |
62. File Input performance coderanch.comI have a few massive text files I have to sort through and move. I'm having a seperate thread for each text file use a FileInputStream and several FileWriters to bring the data in, check where it belongs, and then put it there. Is this the best way to handle this? It seems like its rathers slow (old visual basic version ... |
63. Performance Problem? coderanch.comI have web application. I have a file which has 2 million records, each record is of one line however size is variable but max 32 characters. I display records on page (1,000 records a page). Here user can add record as well as modify/edit record as all 1000 records shown on page can be modified. Also user may delete record ... |
64. How to measure performance improvement over unbuffered file I/O? coderanch.comI've a piece of code that does quite a lot of file I/O. The application is running on Solaris. Gotten a lot of high system CPU utilization and read somewhere that this is due to unbuffered I/Os. So I rewrote the code and uses buffers for it. How do I quantitatively shows that the buffered codes is better than the unbuffered ... |
65. Permission control: File Upload and Download - Want to improve performance coderanch.comGreetings, I have a web app (running in Tomcat) which allows user to login and upload files. The uploaded files are saved to /WEB-INF/resources/user_name/filename The uploaded files should only be available to the uploader. So, when the user login and try to download the files they uploaded, I use a URL pattern /data/user_name/filename and map this pattern to a servlet. When ... |
66. Best performance: read a huge file coderanch.comI am thinking a performance issue. If I have a huge txt file (say, 4GB), like name1,address1,date1......\n name2,address2,date2......\n ..... I need to read it, parse it, make some conversion(i.e, change data format) and then save it to database. Which way we could get the best performance ? what collection type (vector, arraylist?) we need to use ? So far, one thing ... |
67. best performance / practices for read and parse files ? coderanch.comIt's hard to say in advance if there would be any benefit in making this a multi-threaded program. I'd just start with writing a small and simple single-threaded program that does a batch update for every N records (and you'd have to try out which value of N works best). If the performance is not good enough, try more complicated things ... |
68. object-encapsulation vs performance / class-file-size coderanch.comI have a object and I am not sure to place a (long) method within this object to set some properties which only belongs to this object-instance. What if I retrieve (for example, 100000) object-instances. Would it be not better, to place this (long) method out of that object-instance in a separate class (for example, a business-class) and invoke it from ... |
69. IO and Performance java-forums.orgHi Guys, I am facing a performance related issue in my code. Below is the code snippet. public static Map |
70. performance in scanning and manage many files. Can I improve? forums.oracle.comYes, I know is odd code; but the idea was if you expert see something odd that can eat performance. For example I was wondering if I could work around method "read" and on the scanner part. I don't know fine ho exception work, so I'll read about it, thanks, EDIT: I don't understand the part of exception: could you briefly ... |
71. looking for performance boost to java.nio.charset.encode(String) method forums.oracle.comSo if it was reduced to zero time your application would now be 1.00/0.96 = 1.0416666666666666666666666666667 times as fast. The rule of thumb in software engineering is that if you can't make it 10 times as fast don't bother. The hardware will make it twice as fast in 18 months' time anyway. Stressing about an improvement factor of 1.0416 is a ... |
72. bad file reading performance on Mysaify JVM forums.oracle.com |
73. File processing : how could C# have better performance than Java ? forums.oracle.comMicrobenchmarks are notoriously problematic in modern VM-based systems, because they can get useless results, due to just-in-time compilation. Java for example uses HotSpot, which will usually interpet your Java code and track which code gets executed often. If it finds such a "hot spot" (code which is executed repeatedly), then it will produce an optimized, native-code version that is executed from ... |
74. bad performance of File.renameTo() forums.oracle.comi use Fil.renameTo()methode to move 100k files from a folder to another.Both the folder are in the same mount. Os:solaris 10 JDK:1.4.2 When have 20 concurreny users , the performance is bad. this is the time used to move:(unit ms) 07/24 14:02:01 596=== 07/07/24 14:02:01 3423=== 07/07/24 14:02:02 3567=== 07/07/24 14:02:02 3851=== 07/07/24 14:02:02 3256=== 07/07/24 14:02:02 3646=== 07/07/24 14:02:02 3048=== ... |
75. Copy File - performance / interruption forums.oracle.comWhen I use buffersize = (64 * 1024 * 1024) - (32 * 1024); - advantage: it is ~20% faster - disadvatange: it takes up 5-10 seconds until it stops, when user hit the stop button I tried with buffersize 16384, which is 2^14, so it is the happy medium. It is fast enough with the current approach I am using, ... |
76. File I/O - Performance design forums.oracle.comI would like a design solution on File I/O I have a nighlty batch process, which reads records from a flat file, validates the records, creates error for records if any and update the file status in database. The text file can have 500,000 or more records. Design I have thought of: 1) Iterate through records using BufferedReader, create a POJO, ... |