FAQ
Hi,
I am new to hadoop programming. I am trying to copy a local file to HDFS. My
code snippet is:
.
.
Configuration conf = new Configuration();

InputStream in=null;
OutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(src));

FileSystem fs = FileSystem.get(URI.create(dest), conf); *//line:42.
Exception here*

if(fs == null)
System.out.println("fs is null");
else
System.out.println("fs is not null");

out = fs.create(new Path(dest), true);
IOUtils.copyBytes(in, out, conf, true);

System.out.println(dest +" is created successfully.");

} catch (IOException e) {
IOUtils.closeStream(out);
IOUtils.closeStream(in);
throw e;
}
.
.
and when I run it, I got exception:
Exception in thread "main" java.lang.NullPointerException

at org.apache.hadoop.conf.Configuration.get(Configuration.java:436)

at
org.apache.hadoop.fs.FileSystem.getDefaultUri(FileSystem.java:103)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:95)

at HDFSFile.create(HDFSFile.java:42)

at HDFSFile.main(HDFSFile.java:130)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at
java.lang.reflect.Method.invoke(Method.java:616)

at org.apache.hadoop.util.RunJar.main(RunJar.java:156

After dug into source code of hdfs, I found the problem happens at
"Configuration.getProps()". The value of getProps() is null and, obviously,
it shouldn't be.

I couldn't figure out why this happen. Please help me out here.
Appreciate!

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  • Chaitanya krishna at Jun 24, 2010 at 6:51 am
    Hi Elton,

    Can you mention the hadoop version? Also, can you double-check if you set
    "fs.default.name" property correctly in conf/hdfs-site.xml?

    -Chaitanya.
    On Thu, Jun 24, 2010 at 12:12 PM, elton sky wrote:

    Hi,
    I am new to hadoop programming. I am trying to copy a local file to HDFS.
    My
    code snippet is:
    .
    .
    Configuration conf = new Configuration();

    InputStream in=null;
    OutputStream out = null;
    try {
    in = new BufferedInputStream(new FileInputStream(src));

    FileSystem fs = FileSystem.get(URI.create(dest), conf);
    *//line:42.
    Exception here*

    if(fs == null)
    System.out.println("fs is null");
    else
    System.out.println("fs is not null");

    out = fs.create(new Path(dest), true);
    IOUtils.copyBytes(in, out, conf, true);

    System.out.println(dest +" is created successfully.");

    } catch (IOException e) {
    IOUtils.closeStream(out);
    IOUtils.closeStream(in);
    throw e;
    }
    .
    .
    and when I run it, I got exception:
    Exception in thread "main" java.lang.NullPointerException

    at org.apache.hadoop.conf.Configuration.get(Configuration.java:436)

    at
    org.apache.hadoop.fs.FileSystem.getDefaultUri(FileSystem.java:103)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:95)

    at HDFSFile.create(HDFSFile.java:42)

    at HDFSFile.main(HDFSFile.java:130)

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

    at

    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at

    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at
    java.lang.reflect.Method.invoke(Method.java:616)

    at org.apache.hadoop.util.RunJar.main(RunJar.java:156

    After dug into source code of hdfs, I found the problem happens at
    "Configuration.getProps()". The value of getProps() is null and, obviously,
    it shouldn't be.

    I couldn't figure out why this happen. Please help me out here.
    Appreciate!

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groupcommon-dev @
categorieshadoop
postedJun 24, '10 at 6:43a
activeJun 24, '10 at 6:51a
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websitehadoop.apache.org...
irc#hadoop

2 users in discussion

Chaitanya krishna: 1 post Elton sky: 1 post

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