1、内存不够

[ERROR] PermGen space -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors,re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, 
please read the following articles:
[ERROR] [Help 1]http://cwiki.apache.org/confluence/display/MAVEN/OutOfMemoryError

上面这个错误是因为编译的时候内存不够导致的，可以在编译的时候加大内存。

export MAVEN_OPTS="-Xmx2g -XX:MaxPermSize=512M -XX:ReservedCodeCacheSize=512m"

2、缺少scala依赖

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:
run (default) on project spark-core_2.10: An Ant BuildException has occured: 
Please set the SCALA_HOME (or SCALA_LIBRARY_PATH if scala is on the path) 
environment variables and retry.
[ERROR] around Ant part ...<fail message="Please set the SCALA_HOME 
(or SCALA_LIBRARY_PATH if scala is on the path) environment variables and retry.">
@ 6:126 in /export1/spark/spark-0.9.0-incubating/core/target/antrun/build-main.xml

上面这个错误已经写的很清楚了，因为编译Spark的时候需要用到scala，所以得去下载scala，此处编译我用的是2.10.3版本，安装如下：

[wyp@master spark]$ wget http://www.scala-lang.org/files/archive/scala-2.10.3.tgz
[wyp@master spark]$ tar -zxf scala-2.10.3.tgz
[wyp@master spark]$ export SCALA_HOME=/export1/spark/scala-2.10.3

3、mqtt-client-0.4.0无法下载

[error] Server access Error: sun.security.validator.ValidatorException: 
PKIX path building failed: 
sun.security.provider.certpath.SunCertPathBuilderException: 
unable to find valid certification path to requested target 
url=https://repo.eclipse.org/content/repositories/paho-releases/
        org/eclipse/paho/mqtt-client/0.4.0/mqtt-client-0.4.0.pom
[warn] 	module not found: org.eclipse.paho#mqtt-client;0.4.0

这个错误是Maven无法下载mqtt-client-0.4.0.pom，因为他用到的是HTTPS协议。解决这个错误可以通过添加对repo.eclipse.org的信任从而解决这个问题。那如何解决呢？下载InstallCert.java类：

/**
 * http://blogs.sun.com/andreas/resource/InstallCert.java
 * Use:
 * java InstallCert hostname
 * Example:
 *% java InstallCert ecc.fedora.redhat.com
 */

import javax.net.ssl.*;
import java.io.*;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * Class used to add the server's certificate to the KeyStore
 * with your trusted certificates.
 */
public class InstallCert {

    public static void main(String[] args) throws Exception {
        String host;
        int port;
        char[] passphrase;
        if ((args.length == 1) || (args.length == 2)) {
            String[] c = args[0].split(":");
            host = c[0];
            port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
            String p = (args.length == 1) ? "changeit" : args[1];
            passphrase = p.toCharArray();
        } else {
            System.out.println("Usage: java InstallCert <host>[:port"+
                               "[passphrase]");
            return;
        }

        File file = new File("jssecacerts");
        if (file.isFile() == false) {
            char SEP = File.separatorChar;
            File dir = new File(System.getProperty("java.home") + SEP
                    + "lib" + SEP + "security");
            file = new File(dir, "jssecacerts");
            if (file.isFile() == false) {
                file = new File(dir, "cacerts");
            }
        }
        System.out.println("Loading KeyStore " + file + "...");
        InputStream in = new FileInputStream(file);
        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
        ks.load(in, passphrase);
        in.close();

        SSLContext context = SSLContext.getInstance("TLS");
        TrustManagerFactory tmf =
                TrustManagerFactory.getInstance(
                                TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ks);
        X509TrustManager defaultTrustManager = 
                              (X509TrustManager) tmf.getTrustManagers()[0];
        SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
        context.init(null, new TrustManager[]{tm}, null);
        SSLSocketFactory factory = context.getSocketFactory();

        System.out.println("Opening connection to " + host + ":" + port + "...");
        SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
        socket.setSoTimeout(10000);
        try {
            System.out.println("Starting SSL handshake...");
            socket.startHandshake();
            socket.close();
            System.out.println();
            System.out.println("No errors, certificate is already trusted");
        } catch (SSLException e) {
            System.out.println();
            e.printStackTrace(System.out);
        }

        X509Certificate[] chain = tm.chain;
        if (chain == null) {
            System.out.println("Could not obtain server certificate chain");
            return;
        }

        BufferedReader reader =
                new BufferedReader(new InputStreamReader(System.in));

        System.out.println();
        System.out.println("Server sent " + chain.length + " certificate(s):");
        System.out.println();
        MessageDigest sha1 = MessageDigest.getInstance("SHA1");
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        for (int i = 0; i < chain.length; i++) {
            X509Certificate cert = chain[i];
            System.out.println
                    (" " + (i + 1) + " Subject " + cert.getSubjectDN());
            System.out.println("   Issuer  " + cert.getIssuerDN());
            sha1.update(cert.getEncoded());
            System.out.println("   sha1    " + toHexString(sha1.digest()));
            md5.update(cert.getEncoded());
            System.out.println("   md5     " + toHexString(md5.digest()));
            System.out.println();
        }

        System.out.println("Enter certificate to add to trusted keystore or"+
                           " 'q' to quit: [1]");
        String line = reader.readLine().trim();
        int k;
        try {
            k = (line.length() == 0) ? 0 : Integer.parseInt(line) - 1;
        } catch (NumberFormatException e) {
            System.out.println("KeyStore not changed");
            return;
        }

        X509Certificate cert = chain[k];
        String alias = host + "-" + (k + 1);
        ks.setCertificateEntry(alias, cert);

        OutputStream out = new FileOutputStream("jssecacerts");
        ks.store(out, passphrase);
        out.close();

        System.out.println();
        System.out.println(cert);
        System.out.println();
        System.out.println
                ("Added certificate to keystore 'jssecacerts' using alias '"
                        + alias + "'");
    }

    private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();

    private static String toHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder(bytes.length * 3);
        for (int b : bytes) {
            b &= 0xff;
            sb.append(HEXDIGITS[b >> 4]);
            sb.append(HEXDIGITS[b & 15]);
            sb.append(' ');
        }
        return sb.toString();
    }

    private static class SavingTrustManager implements X509TrustManager {

        private final X509TrustManager tm;
        private X509Certificate[] chain;

        SavingTrustManager(X509TrustManager tm) {
            this.tm = tm;
        }

        public X509Certificate[] getAcceptedIssuers() {
            throw new UnsupportedOperationException();
        }

        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            throw new UnsupportedOperationException();
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            this.chain = chain;
            tm.checkServerTrusted(chain, authType);
        }
    }

}

编译上面的类：

$ javac InstallCert.java
$ java InstallCert repo.eclipse.org

这样会在当前目录下面生成名为jssecacerts的文件，将这个文件拷贝到你java安装目录的$JAVA_HOME/lib/security/下面，然后上述问题即可解决。