According to the [API docs](http://docs.oracle.com/javase/7/docs/api/java/lang/Character.html), isLetter() returns true if the character has any of the following general category types: UPPERCASE_LETTER (Lu), LOWERCASE_LETTER (Ll), TITLECASE_LETTER (Lt), MODIFIER_LETTER (Lm), OTHER_LETTER (Lo). If we compare isAlphabetic(), it has the same but adds LETTER_NUMBER (Nl), and also any characters having Other_Alphabetic property.

What does this mean in practice? Every letter is alphabetic, but not every alphabetic is a letter - in Java 7 (which uses Unicode 6.0.0), there are 824 characters in the BMP which are alphabetic but not letters. Some examples include 0345 (a combiner used in polytonic Greek), Hebrew vowel points (niqqud) starting at 05B0, Arabic honorifics such as saw (&quot;peace be upon him&quot;) at 0610, Arabic vowel points... the list goes on.

But basically, for English text, the distinction makes no difference. For some other languages, the distinction might make a difference, but it is hard to predict in advance what the difference might be in practice. If one has a choice, the best answer may be isLetter() - one can always change to permit additional characters in the future, but reducing the set of accepted characters might be harder.

There is a column of type `text` in a table in Postgres 9.1. I&#39;d like to know the impact of just that column on the disk space needed. It doesn&#39;t need to be precise, but I&#39;d like to get an idea if that column is responsible for 20%/30%/... of the disk space consumed by the database.

I know `pg_relation_size`, but it only operates at table level.

I have many databases with this same schema. I dumped a smaller one and cut out the column with grep and cut and compared the size of the plain text dumps. But this is not necessarily a good indicator of space requirements in the live db, and it&#39;s also more difficult to do that for large databases.



How to estimate the size of one column in a Postgres table?

I have a huge file that I am writing into approximately 450 files. I am getting error as `too many files open`. I searched the web and found some solution but it is not helping. 

    import resource
    resource.setrlimit(resource.RLIMIT_NOFILE, (1000,-1))
    &gt;&gt;&gt; len(pureResponseNames) #Filenames 
    434
    &gt;&gt;&gt; resource.getrlimit(resource.RLIMIT_NOFILE)
    (1000, 9223372036854775807)
    &gt;&gt;&gt; output_files = [open(os.path.join(outpathDirTest, fname) + &quot;.txt&quot;, &quot;w&quot;) for fname in pureResponseNames]
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    IOError: [Errno 24] Too many open files: &#39;icd9_737.txt&#39;
    &gt;&gt;&gt; 


I also changed `ulimit` from the command line as below:

    $ ulimit -n 1200
    $ ulimit -a
    core file size          (blocks, -c) 0
    data seg size           (kbytes, -d) unlimited
    file size               (blocks, -f) unlimited
    max locked memory       (kbytes, -l) unlimited
    max memory size         (kbytes, -m) unlimited
    open files                      (-n) 1200
    pipe size            (512 bytes, -p) 1
    stack size              (kbytes, -s) 8192
    cpu time               (seconds, -t) unlimited
    max user processes              (-u) 709
    virtual memory          (kbytes, -v) unlimited
    $ 


I am still getting the same error. 
PS: I also restarted my system and run the program but with no success. 



IOError: [Errno 24] Too many open files:

What is the difference between Character.isAlphabetic() and Character.isLetter() in Java? When should one use one and when should one use the other?

What is the difference between Character.isAlphabetic and Character.isLetter in Java?

<p>What is the difference between Character.isAlphabetic() and Character.isLetter() in Java? When should one use one and when should one use the other?</p>


Consider the following code.

&lt;!-- language-all: lang-java --&gt;


    public class Action {
    private static int i=1;
    public static void main(String[] args) {
        try{
            System.out.println(i);
            i++;
            main(args);
        }catch (StackOverflowError e){
            System.out.println(i);
            i++;
            main(args);
        }
     }

    }

I am getting i value up to `4338` correctly. After catching the `StackOverflowError` output getting wired as follows.

    4336
    4337
    4338 // up to this point out put can understand 
    433943394339 // 4339 repeating thrice  
    434043404340
    4341
    434243424342
    434343434343
    4344
    4345
    434643464346
    434743474347
    4348
    434943494349
    435043504350

Consider [Live][1] demo here. It is working correctly up to `i=4330`. Actually how this happen?  


***FYI:***

I did following code to realize what is happening here.


    public class Action {
    
        private static int i = 1;
        private static BufferedWriter bw;
    
        static {
            try {
                bw = new BufferedWriter(new FileWriter(&quot;D:\\sample.txt&quot;));
            } catch (IOException e) {
               e.printStackTrace();
            }
        }
    
        public static void main(String[] args) throws IOException {
            bw.append(String.valueOf(i)+&quot; &quot;);
            try {
                i++;
                main(args);
            } catch (StackOverflowError e) {
                bw.append(String.valueOf(i)+&quot; &quot;);
                i++;
                main(args);
            }
        }
    
    }

Now previous issue not there. now value of `i` up to `16824744` correct and and runs further. I am hopping this may runs up to value of `i=2,147,483,647`(max value of int) without an issue.

There is some issue with `println()`. There are similar answers bellow too. But why? 

What will be the actual reason?
 

  [1]: http://ideone.com/rqX0jv


Confusing output from infinite recursion within try-catch

I want to change the system brightness programmatically. For that purpose I am using this code:

    WindowManager.LayoutParams lp = window.getAttributes();
    lp.screenBrightness = (255);
    window.setAttributes(lp);

because I heard that max value is 255.

but it does nothing. Please suggest any thing that can change the brightness.
Thanks

Change the System Brightness Programmatically

I have a problem in my custom deserializer in Jackson. I want to access the default serializer to populate the object I am deserializing into. After the population I will do some custom things but first I want to deserialize the object with the default Jackson behavior.

This is the code that I have at the moment.

    public class UserEventDeserializer extends StdDeserializer&lt;User&gt; {
    
      private static final long serialVersionUID = 7923585097068641765L;
    
      public UserEventDeserializer() {
        super(User.class);
      }
    
      @Override
      @Transactional
      public User deserialize(JsonParser jp, DeserializationContext ctxt)
          throws IOException, JsonProcessingException {
        
        ObjectCodec oc = jp.getCodec();
        JsonNode node = oc.readTree(jp);
        User deserializedUser = null;
        deserializedUser = super.deserialize(jp, ctxt, new User()); 
        // The previous line generates an exception java.lang.UnsupportedOperationException
        // Because there is no implementation of the deserializer.
        // I want a way to access the default spring deserializer for my User class.
        // How can I do that?
    
        //Special logic
        
        return deserializedUser;
      }
    
    }

What I need is a way to initialize the default deserializer so that I can pre-populate my POJO before I start my special logic.

When calling deserialize from within the custom deserializer It seems the method is called from the current context no matter how I construct the serializer class. Because of the annotation in my POJO. This causes a Stack Overflow exception for obvious reasons.

I have tried initializing a `BeanDeserializer` but the process is extremely complex and I haven&#39;t managed to find the right way to do it. I have also tried overloading the `AnnotationIntrospector` to no avail, thinking that it might help me ignore the annotation in the `DeserializerContext`. Finally it seams I might have had some success using `JsonDeserializerBuilders` although this required me to do some magic stuff to get hold of the application context from Spring. I would appreciate any thing that could lead me to a cleaner solution for example how Can I construct a deserialization context without reading the `JsonDeserializer` annotation.


How do I call the default deserializer from a custom deserializer in Jackson

I have a JDK 1.7 project with a maven dependency to a local jar in my maven repo.

I&#39;m unable to build the project using Intellij, with the errors that a symbol cannot be found (the symbol is a class importing packages from the local jar)

But I can successfully build the project using &#39;mvn package&#39;.

I&#39;ve spent so much time looking for solutions, things I&#39;ve already done:

- Invalidated cache
- &#39;mvn clean install&#39; the local jar dependecy
- Marked to &#39;autoload snapshots&#39; in Intellij&#39;s maven configuration
- Reimpoted maven in Intellij
- Syncornized

This error happend to my couple of times before, but usually just closing the Intellij and /or doing the &#39;mvn clean install&#39; did the trick.

Please help.

Maven package works but Intellij&#39;s build fails

I am using jackson 2.2 annotation @JsonProperty with required set to true. While deserializing json file which doesn&#39;t contain that property via ObjectMapper readValue() method no exception is being thrown.
Is it supposed to work in a different way or did I missed something?

My dto class:

    public class User {
        public enum Gender {MALE, FEMALE}
    
        ;
    
        public static class Name {
            private String _first, _last;
    
            public String getFirst() {
                return _first;
            }
    
            public String getLast() {
                return _last;
            }
    
            public void setFirst(String s) {
                _first = s;
            }
    
            public void setLast(String s) {
                _last = s;
            }
        }
    
        private Gender _gender;
        private Name _name;
        private boolean _isVerified;
        private byte[] _userImage;
    
        @JsonProperty(value =&quot;NAAME&quot;,required = true)
        public Name getName() {
            return _name;
        }
    
        @JsonProperty(&quot;VERIFIED&quot;)
        public boolean isVerified() {
            return _isVerified;
        }
    
        @JsonProperty(&quot;GENDER&quot;)
        public Gender getGender() {
            return _gender;
        }
        @JsonProperty(&quot;IMG&quot;)
        public byte[] getUserImage() {
            return _userImage;
        }
    
        @JsonProperty(value =&quot;NAAME&quot;,required = true)
        public void setName(Name n) {
            _name = n;
        }
        @JsonProperty(&quot;VERIFIED&quot;)
        public void setVerified(boolean b) {
            _isVerified = b;
        }
        @JsonProperty(&quot;GENDER&quot;)
        public void setGender(Gender g) {
            _gender = g;
        }
        @JsonProperty(&quot;IMG&quot;)
        public void setUserImage(byte[] b) {
            _userImage = b;
        }
    }

This is how do I deserialize the class:

    public class Serializer {
        private ObjectMapper mapper;
    
        public Serializer() {
            mapper = new ObjectMapper();
            SimpleModule sm = new SimpleModule(&quot;PIF deserialization&quot;);
            mapper.registerModule(sm);
        }
    
        public void writeUser(File filename, User user) throws IOException {
            mapper.writeValue(filename, user);
        }
    
        public User readUser(File filename) throws IOException {
              return mapper.readValue(filename, User.class);
          }
    }

This is how it is actually called:

        Serializer serializer = new Serializer();
        User result = serializer.readUser(new File(&quot;user.json&quot;));

Actuall json looks like:

    {&quot;GENDER&quot;:&quot;FEMALE&quot;,&quot;VERIFIED&quot;:true,&quot;IMG&quot;:&quot;AQ8=&quot;}

I would expect that since _name is not specified in json file and is required that the exception will be thrown.

Jackson @JsonProperty(required=true) doesn&#39;t throw an exception

Sample code:

    &gt;&gt;&gt; import json
    &gt;&gt;&gt; json_string = json.dumps(&quot;ברי צקלה&quot;)
    &gt;&gt;&gt; print(json_string)
    &quot;\u05d1\u05e8\u05d9 \u05e6\u05e7\u05dc\u05d4&quot;

The problem: it&#39;s not human readable. My (smart) users want to verify or even edit text files with JSON dumps (and I’d rather not use XML).

Is there a way to serialize objects into UTF-8 JSON strings (instead of  `\uXXXX`)?

Saving utf-8 texts with json.dumps as UTF8, not as \u escape sequence

What&#39;s the exact difference between Unicode and ASCII?

ASCII has a total of 128 characters (256 in the extended set).

Is there any size specification for Unicode characters?

What&#39;s the difference between ASCII and Unicode?

I want to describe directory &amp; file structures in some of my Jekyll blog posts, does Markdown provide a neat way of outputting such a thing?

For example, you can see **[at this link](http://jekyllrb.com/docs/structure/)** on the Jekyll website that the directory &amp; file structure is output on the page very neatly:

```
.
├── _config.yml
├── _drafts
│   ├── begin-with-the-crazy-ideas.textile
│   └── on-simplicity-in-technology.markdown
├── _includes
│   ├── footer.html
│   └── header.html
├── _layouts
│   ├── default.html
│   └── post.html
├── _posts
│   ├── 2007-10-29-why-every-programmer-should-play-nethack.textile
│   └── 2009-04-26-barcamp-boston-4-roundup.textile
├── _data
│   └── members.yml
├── _site
└── index.html
```

I believe the line block characters above are Unicode (as described in **[this answer here](https://softwareengineering.stackexchange.com/questions/118640/write-a-directory-structure-pseudo-code)**), but I am not sure how Markdown or different browsers will handle them. I was hoping that Markdown had included some way of doing this which outputs as the Unicode characters above perhaps.

Representing Directory &amp; File Structure in Markdown Syntax

I am trying to use a Python package called bidi. In a module in this package (algorithm.py) there are some lines that give me error, although it is part of the package.

Here are the lines:

    # utf-8 ? we need unicode
    if isinstance(unicode_or_str, unicode):
        text = unicode_or_str
        decoded = False
    else:
        text = unicode_or_str.decode(encoding)
        decoded = True

and here is the error message:

    Traceback (most recent call last):
      File &quot;&lt;pyshell#25&gt;&quot;, line 1, in &lt;module&gt;
        bidi_text = get_display(reshaped_text)
      File &quot;C:\Python33\lib\site-packages\python_bidi-0.3.4-py3.3.egg\bidi\algorithm.py&quot;,   line 602, in get_display
        if isinstance(unicode_or_str, unicode):
    NameError: global name &#39;unicode&#39; is not defined

How should I re-write this part of the code so it works in Python3?
Also if anyone have used bidi package with Python 3 please let me know if they have found similar problems or not. I appreciate your help.


NameError: global name &#39;unicode&#39; is not defined - in Python 3

I need to replace all non-ASCII (\x00-\x7F) characters with a space. I&#39;m surprised that this is not dead-easy in Python, unless I&#39;m missing something. The following function simply removes all non-ASCII characters:

    def remove_non_ascii_1(text):
    
        return &#39;&#39;.join(i for i in text if ord(i)&lt;128)

And this one replaces non-ASCII characters with the amount of spaces as per the amount of bytes in the character code point (i.e. the `–` character is replaced with 3 spaces):

    def remove_non_ascii_2(text):
    
        return re.sub(r&#39;[^\x00-\x7F]&#39;,&#39; &#39;, text)

**How can I replace all non-ASCII characters with a single space?**

[Of](https://stackoverflow.com/questions/1342000/how-to-replace-non-ascii-characters-in-string) [the](https://stackoverflow.com/questions/196345/how-to-check-if-a-string-in-python-is-in-ascii) [myriad](https://stackoverflow.com/questions/6609895/efficiently-replace-bad-characters) [of](https://stackoverflow.com/questions/92438/stripping-non-printable-characters-from-a-string-in-python) [similar](https://stackoverflow.com/questions/15737048/handle-non-ascii-code-string-in-python) [SO](https://stackoverflow.com/questions/8689795/python-remove-non-ascii-characters-but-leave-periods-and-spaces) [questions](https://stackoverflow.com/questions/2921815/help-replacing-non-ascii-character-in-python), [none](https://stackoverflow.com/questions/17273575/python-replace-non-ascii-characters-in-a-list-of-strings) [address](https://stackoverflow.com/questions/16866261/detecting-non-ascii-characters-in-unicode-string) [character](https://stackoverflow.com/questions/3667875/removing-non-ascii-characters-from-any-given-stringtype-in-python) [replacement](https://stackoverflow.com/questions/19000968/what-is-the-correct-way-to-use-unicode-characters-in-a-python-regex) [as](https://stackoverflow.com/questions/10993612/python-removing-xa0-from-string) [opposed](https://stackoverflow.com/questions/3586903/sqlite-remove-non-utf-8-characters) [to](https://stackoverflow.com/questions/15321138/removing-unicode-u2026-like-characters-in-a-string-in-python2-7) [stripping](https://stackoverflow.com/questions/18522127/removing-non-ascii-characters-in-a-csv-file), [and ](https://stackoverflow.com/questions/3870084/how-to-decode-a-non-unicode-character-in-python) [additionally]() [address]() [all]() [non-ascii]() [characters]() [not]()  [a]()  [specific]()  [character]().

Content Type	Original Author	Original Content on Stackoverflow
Question	Simon Kissane	View Question on Stackoverflow
Solution 1 - Java	Simon Kissane	View Answer on Stackoverflow

What is the difference between Character.isAlphabetic and Character.isLetter in Java?

Java Problem Overview

Java Solutions

Solution 1 - Java

IOError: [Errno 24] Too many open files:

How to estimate the size of one column in a Postgres table?

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