Dear Arko,
The class org.apache.hadoop.fs.Path is available in the hadoop-common-0.21.0.jar. >From your code I can see you are trying to create a file in HDFS and write into it. The code snippet needs the hdfs and common jar for compiling. Regards, Subroto Sanyal _____ From: Arko Provo Mukherjee [mailto:arkoprovomukher...@gmail.com] Sent: Friday, September 02, 2011 10:18 AM To: mapreduce-user@hadoop.apache.org Subject: Re: Compiling programs with Hadoop 0.21.0 Hello, Thanks for your reply. Following your suggestion, I tried to compile using the following command: $ javac -classpath /Users/arko/Documents/hadoop-0.21.0/hadoop-hdfs-0.21.0.jar -d class/ FileTest.java I got the following errors: FileTest.java:9: package org.apache.hadoop does not exist import org.apache.hadoop.*; ^ FileTest.java:16: cannot find symbol symbol : class Path location: class FileTest Path pt=new Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc"); ^ FileTest.java:16: cannot find symbol symbol : class Path location: class FileTest Path pt=new Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc"); ^ FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be accessed from outside package FileSystem fs = FileSystem.get(new Configuration()); ^ FileTest.java:17: cannot find symbol symbol : class Configuration location: class FileTest FileSystem fs = FileSystem.get(new Configuration()); ^ FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be accessed from outside package FileSystem fs = FileSystem.get(new Configuration()); ^ 6 errors Many thanks in advance! Warm regards Arko On Thu, Sep 1, 2011 at 10:13 PM, Rottinghuis, Joep <jrottingh...@ebay.com> wrote: > Hadoop-hdfs will contain the HDFS (Hadoop FileSystem) classes. > > In your code you point to hdfs:// in your path, therefore you use HDFS, > hence they are needed. > > > > Add the hdfs jar to your classpath and see if that improves things. > > > > Iif you organize imports on you class in an IDE such as Eclipse you'll see > that when you restrict the org.apache.hadoop.* import only to packages you > need, that indeed you are using hdfs classes. > > > > Thanks, > > > > Joep > > > > From: Arko Provo Mukherjee [mailto:arkoprovomukher...@gmail.com] > Sent: Wednesday, August 31, 2011 5:40 PM > To: mapreduce-user@hadoop.apache.org > Subject: Re: Compiling programs with Hadoop 0.21.0 > > > > Hi, > > > > Thanks for the kind reply. > > > > If only the common and mapred are used, then what is hadoop-hdfs-0.21.0.jar > used for? > > > > My code looks like this: > > > > import java.util.*; > > import java.lang.*; > > import java.io.*; > > import org.apache.hadoop.*; > > > > class MapReduce { > > > > public static void main(String[] args) throws Exception { > > try { > > Path pt=new > Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc"); > > FileSystem fs = FileSystem.get(new Configuration()); > > BufferedWriter br=new BufferedWriter(new > OutputStreamWriter(fs.create(pt,true))); > > String line; > > line="Testing"; > > System.out.println(line); > > br.write(line); > > br.close(); > > }catch(Exception e){ > > System.out.println("File not found"); > > } > > } > > } > > > > When I compile the code, I get the following erros: > > $javac -classpath > /Users/arko/Documents/hadoop-0.21.0/hadoop-common-0.21.0.jar -d class/ > FileSystemCat.java clear > > > > FileTest.java:16: cannot find symbol > > symbol : class Path > > location: class FileTest > > Path pt=new > Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc"); > > ^ > > FileTest.java:16: cannot find symbol > > symbol : class Path > > location: class FileTest > > Path pt=new > Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc"); > > ^ > > FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be > accessed from outside package > > FileSystem fs = FileSystem.get(new Configuration()); > > ^ > > FileTest.java:17: cannot find symbol > > symbol : class Configuration > > location: class FileTest > > FileSystem fs = FileSystem.get(new Configuration()); > > ^ > > FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be > accessed from outside package > > FileSystem fs = FileSystem.get(new Configuration()); > > ^ > > 5 errors > > > > Thanks again for help! > Warm Regards > > Arko > > On Wed, Aug 31, 2011 at 5:00 PM, Robert Evans <ev...@yahoo-inc.com> wrote: > > You should be able to use hadoop-common-0.21.0.jar for accessing HDFS APIS > and use hadoop-mapred.0.21.0.jar for accessing the mapreduce APIs. I cannot > really comment further on compilation errors without seeing the code/error > messages. > > --Bobby Evans > > On 8/31/11 4:34 PM, "Arko Provo Mukherjee" <arkoprovomukher...@gmail.com> > wrote: > > Hello, > > I am trying to learn Hadoop and doing a project on it. > > I need to update some files in my project and hence wanted to use version > 0.21.0 > > However, I am confused as to how I can compile my programs on version 0.21.0 > as it doesn't have any hadoop-core-0.21.0.jar file. What option should I > have to give in the -classpath option? > I can see three different JAR files namely hadoop-common-0.21.0.jar, > hadoop-hdfs-0.21.0.jar & hadoop-mapred-0.21.0.jar. > > I am getting compilation errors which using the the common jar file. > > Also I would like to learn the FileContext Library as the docs that I have > read says that it has a simpler interface than the FileSystem. However, I > cannot find any links to some example code which can help me to grasp the > API. Request you to kindly share any link / code snippet to demonstrate the > use of the new API. > > Many thanks in advance for your kind response. > > Warm regards > Arko > >
