diff --git a/core/src/main/java/hudson/Util.java b/core/src/main/java/hudson/Util.java
index 2934a79a4f9ec629b4bb267c172187054cc8ef7f..b7725aa68fcba854bb08034d77412e07cee83bd1 100644
--- a/core/src/main/java/hudson/Util.java
+++ b/core/src/main/java/hudson/Util.java
@@ -73,6 +73,9 @@ import hudson.util.jna.Kernel32Utils;
 
 import static hudson.util.jna.GNUCLibrary.LIBC;
 import java.security.DigestInputStream;
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import org.apache.commons.codec.digest.DigestUtils;
 
 /**
@@ -94,7 +97,8 @@ public class Util {
      * Creates a filtered sublist.
      * @since 1.176
      */
-    public static <T> List<T> filter( Iterable<?> base, Class<T> type ) {
+    @Nonnull
+    public static <T> List<T> filter( @Nonnull Iterable<?> base, @Nonnull Class<T> type ) {
         List<T> r = new ArrayList<T>();
         for (Object i : base) {
             if(type.isInstance(i))
@@ -106,7 +110,8 @@ public class Util {
     /**
      * Creates a filtered sublist.
      */
-    public static <T> List<T> filter( List<?> base, Class<T> type ) {
+    @Nonnull
+    public static <T> List<T> filter( @Nonnull List<?> base, @Nonnull Class<T> type ) {
         return filter((Iterable)base,type);
     }
 
@@ -122,7 +127,8 @@ public class Util {
      * Unlike shell, undefined variables are left as-is (this behavior is the same as Ant.)
      *
      */
-    public static String replaceMacro(String s, Map<String,String> properties) {
+    @Nullable
+    public static String replaceMacro( @CheckForNull String s, @Nonnull Map<String,String> properties) {
         return replaceMacro(s,new VariableResolver.ByMap<String>(properties));
     }
     
@@ -132,7 +138,8 @@ public class Util {
      * <p>
      * Unlike shell, undefined variables are left as-is (this behavior is the same as Ant.)
      */
-    public static String replaceMacro(String s, VariableResolver<String> resolver) {
+    @Nullable
+    public static String replaceMacro(@CheckForNull String s, @Nonnull VariableResolver<String> resolver) {
     	if (s == null) {
     		return null;
     	}
@@ -165,11 +172,13 @@ public class Util {
     /**
      * Loads the contents of a file into a string.
      */
-    public static String loadFile(File logfile) throws IOException {
+    @Nonnull
+    public static String loadFile(@Nonnull File logfile) throws IOException {
         return loadFile(logfile, Charset.defaultCharset());
     }
 
-    public static String loadFile(File logfile,Charset charset) throws IOException {
+    @Nonnull
+    public static String loadFile(@Nonnull File logfile, @Nonnull Charset charset) throws IOException {
         if(!logfile.exists())
             return "";
 
@@ -195,7 +204,7 @@ public class Util {
      * @throws IOException
      *      if the operation fails.
      */
-    public static void deleteContentsRecursive(File file) throws IOException {
+    public static void deleteContentsRecursive(@Nonnull File file) throws IOException {
         File[] files = file.listFiles();
         if(files==null)
             return;     // the directory didn't exist in the first place
@@ -208,7 +217,7 @@ public class Util {
      * @param f a file to delete
      * @throws IOException if it exists but could not be successfully deleted
      */
-    public static void deleteFile(File f) throws IOException {
+    public static void deleteFile(@Nonnull File f) throws IOException {
         if (!f.delete()) {
             if(!f.exists())
                 // we are trying to delete a file that no longer exists, so this is not an error
@@ -259,7 +268,7 @@ public class Util {
     /**
      * Makes the given file writable by any means possible.
      */
-    private static void makeWritable(File f) {
+    private static void makeWritable(@Nonnull File f) {
         if (f.setWritable(true)) {
             return;
         }
@@ -287,7 +296,7 @@ public class Util {
 
     }
 
-    public static void deleteRecursive(File dir) throws IOException {
+    public static void deleteRecursive(@Nonnull File dir) throws IOException {
         if(!isSymlink(dir))
             deleteContentsRecursive(dir);
         try {
@@ -321,7 +330,7 @@ public class Util {
      * Checks if the given file represents a symlink.
      */
     //Taken from http://svn.apache.org/viewvc/maven/shared/trunk/file-management/src/main/java/org/apache/maven/shared/model/fileset/util/FileSetManager.java?view=markup
-    public static boolean isSymlink(File file) throws IOException {
+    public static boolean isSymlink(@Nonnull File file) throws IOException {
         Boolean r = isSymlinkJava7(file);
         if (r != null) {
             return r;
@@ -350,7 +359,7 @@ public class Util {
     }
 
     @SuppressWarnings("NP_BOOLEAN_RETURN_NULL")
-    private static Boolean isSymlinkJava7(File file) throws IOException {
+    private static Boolean isSymlinkJava7(@Nonnull File file) throws IOException {
         try {
             Object path = File.class.getMethod("toPath").invoke(file);
             return (Boolean) Class.forName("java.nio.file.Files").getMethod("isSymbolicLink", Class.forName("java.nio.file.Path")).invoke(null, path);
@@ -379,13 +388,14 @@ public class Util {
      * On Windows, error messages for IOException aren't very helpful.
      * This method generates additional user-friendly error message to the listener
      */
-    public static void displayIOException( IOException e, TaskListener listener ) {
+    public static void displayIOException(@Nonnull IOException e, @Nonnull TaskListener listener ) {
         String msg = getWin32ErrorMessage(e);
         if(msg!=null)
             listener.getLogger().println(msg);
     }
 
-    public static String getWin32ErrorMessage(IOException e) {
+    @CheckForNull
+    public static String getWin32ErrorMessage(@Nonnull IOException e) {
         return getWin32ErrorMessage((Throwable)e);
     }
 
@@ -395,6 +405,7 @@ public class Util {
      * @return
      *      null if there seems to be no error code or if the platform is not Win32.
      */
+    @CheckForNull
     public static String getWin32ErrorMessage(Throwable e) {
         String msg = e.getMessage();
         if(msg!=null) {
@@ -420,6 +431,7 @@ public class Util {
      * @return
      *      null if no such message is available.
      */
+    @CheckForNull
     public static String getWin32ErrorMessage(int n) {
         try {
             ResourceBundle rb = ResourceBundle.getBundle("/hudson/win32errors");
@@ -433,6 +445,7 @@ public class Util {
     /**
      * Guesses the current host name.
      */
+    @Nonnull
     public static String getHostName() {
         try {
             return InetAddress.getLocalHost().getHostName();
@@ -441,21 +454,21 @@ public class Util {
         }
     }
 
-    public static void copyStream(InputStream in,OutputStream out) throws IOException {
+    public static void copyStream(@Nonnull InputStream in,@Nonnull OutputStream out) throws IOException {
         byte[] buf = new byte[8192];
         int len;
         while((len=in.read(buf))>=0)
             out.write(buf,0,len);
     }
 
-    public static void copyStream(Reader in, Writer out) throws IOException {
+    public static void copyStream(@Nonnull Reader in, @Nonnull Writer out) throws IOException {
         char[] buf = new char[8192];
         int len;
         while((len=in.read(buf))>0)
             out.write(buf,0,len);
     }
 
-    public static void copyStreamAndClose(InputStream in,OutputStream out) throws IOException {
+    public static void copyStreamAndClose(@Nonnull InputStream in, @Nonnull OutputStream out) throws IOException {
         try {
             copyStream(in,out);
         } finally {
@@ -464,7 +477,7 @@ public class Util {
         }
     }
 
-    public static void copyStreamAndClose(Reader in,Writer out) throws IOException {
+    public static void copyStreamAndClose(@Nonnull Reader in, @Nonnull Writer out) throws IOException {
         try {
             copyStream(in,out);
         } finally {
@@ -483,18 +496,21 @@ public class Util {
      * @since 1.145
      * @see QuotedStringTokenizer
      */
-    public static String[] tokenize(String s,String delimiter) {
+    @Nonnull
+    public static String[] tokenize(@Nonnull String s, @CheckForNull String delimiter) {
         return QuotedStringTokenizer.tokenize(s,delimiter);
     }
 
-    public static String[] tokenize(String s) {
+    @Nonnull
+    public static String[] tokenize(@Nonnull String s) {
         return tokenize(s," \t\n\r\f");
     }
 
     /**
      * Converts the map format of the environment variables to the K=V format in the array.
      */
-    public static String[] mapToEnv(Map<String,String> m) {
+    @Nonnull
+    public static String[] mapToEnv(@Nonnull Map<String,String> m) {
         String[] r = new String[m.size()];
         int idx=0;
 
@@ -504,7 +520,7 @@ public class Util {
         return r;
     }
 
-    public static int min(int x, int... values) {
+    public static int min(int x, @Nonnull int... values) {
         for (int i : values) {
             if(i<x)
                 x=i;
@@ -512,11 +528,13 @@ public class Util {
         return x;
     }
 
-    public static String nullify(String v) {
+    @CheckForNull
+    public static String nullify(@CheckForNull String v) {
         return fixEmpty(v);
     }
 
-    public static String removeTrailingSlash(String s) {
+    @Nonnull
+    public static String removeTrailingSlash(@Nonnull String s) {
         if(s.endsWith("/")) return s.substring(0,s.length()-1);
         else                return s;
     }
@@ -531,7 +549,8 @@ public class Util {
      *         case subject was null and subject + suffix otherwise.
      * @since 1.505
      */
-    public static String ensureEndsWith(String subject, String suffix) {
+    @Nullable
+    public static String ensureEndsWith(@CheckForNull String subject, @CheckForNull String suffix) {
 
         if (subject == null) return null;
 
@@ -549,7 +568,8 @@ public class Util {
      *      32-char wide string
      * @see DigestUtils#md5Hex(InputStream)
      */
-    public static String getDigestOf(InputStream source) throws IOException {
+    @Nonnull
+    public static String getDigestOf(@Nonnull InputStream source) throws IOException {
         try {
             MessageDigest md5 = MessageDigest.getInstance("MD5");
 
@@ -574,7 +594,8 @@ public class Util {
         */
     }
 
-    public static String getDigestOf(String text) {
+    @Nonnull
+    public static String getDigestOf(@Nonnull String text) {
         try {
             return getDigestOf(new ByteArrayInputStream(text.getBytes("UTF-8")));
         } catch (IOException e) {
@@ -589,7 +610,8 @@ public class Util {
      * @throws IOException in case reading fails
      * @since 1.525
      */
-    public static String getDigestOf(File file) throws IOException {
+    @Nonnull
+    public static String getDigestOf(@Nonnull File file) throws IOException {
         InputStream is = new FileInputStream(file);
         try {
             return getDigestOf(new BufferedInputStream(is));
@@ -602,7 +624,8 @@ public class Util {
      * Converts a string into 128-bit AES key.
      * @since 1.308
      */
-    public static SecretKey toAes128Key(String s) {
+    @Nonnull 
+    public static SecretKey toAes128Key(@Nonnull String s) {
         try {
             // turn secretKey into 256 bit hash
             MessageDigest digest = MessageDigest.getInstance("SHA-256");
@@ -618,7 +641,8 @@ public class Util {
         }
     }
 
-    public static String toHexString(byte[] data, int start, int len) {
+    @Nonnull
+    public static String toHexString(@Nonnull byte[] data, int start, int len) {
         StringBuilder buf = new StringBuilder();
         for( int i=0; i<len; i++ ) {
             int b = data[start+i]&0xFF;
@@ -628,11 +652,13 @@ public class Util {
         return buf.toString();
     }
 
-    public static String toHexString(byte[] bytes) {
+    @Nonnull
+    public static String toHexString(@Nonnull byte[] bytes) {
         return toHexString(bytes,0,bytes.length);
     }
 
-    public static byte[] fromHexString(String data) {
+    @Nonnull
+    public static byte[] fromHexString(@Nonnull String data) {
         byte[] r = new byte[data.length() / 2];
         for (int i = 0; i < data.length(); i += 2)
             r[i / 2] = (byte) Integer.parseInt(data.substring(i, i + 2), 16);
@@ -646,6 +672,7 @@ public class Util {
      * @param duration
      *      number of milliseconds.
      */
+    @Nonnull
     public static String getTimeSpanString(long duration) {
         // Break the duration up in to units.
         long years = duration / ONE_YEAR_MS;
@@ -692,10 +719,11 @@ public class Util {
      * So 13 minutes and 43 seconds returns just "13 minutes", but 3 minutes
      * and 43 seconds is "3 minutes 43 seconds".
      */
+    @Nonnull
     private static String makeTimeSpanString(long bigUnit,
-                                             String bigLabel,
+                                             @Nonnull String bigLabel,
                                              long smallUnit,
-                                             String smallLabel) {
+                                             @Nonnull String smallLabel) {
         String text = bigLabel;
         if (bigUnit < 10)
             text += ' ' + smallLabel;
@@ -707,6 +735,7 @@ public class Util {
      * Get a human readable string representing strings like "xxx days ago",
      * which should be used to point to the occurrence of an event in the past.
      */
+    @Nonnull
     public static String getPastTimeString(long duration) {
         return Messages.Util_pastTime(getTimeSpanString(duration));
     }
@@ -720,7 +749,8 @@ public class Util {
      *   See {@link Messages#Util_year(Object)} for an example.
      *   Deprecated since 2009-06-24, remove method after 2009-12-24.
      */
-    public static String combine(long n, String suffix) {
+    @Nonnull
+    public static String combine(long n, @Nonnull String suffix) {
         String s = Long.toString(n)+' '+suffix;
         if(n!=1)
         	// Just adding an 's' won't work in most natural languages, even English has exception to the rule (e.g. copy/copies).
@@ -731,7 +761,8 @@ public class Util {
     /**
      * Create a sub-list by only picking up instances of the specified type.
      */
-    public static <T> List<T> createSubList( Collection<?> source, Class<T> type ) {
+    @Nonnull
+    public static <T> List<T> createSubList(@Nonnull Collection<?> source, @Nonnull Class<T> type ) {
         List<T> r = new ArrayList<T>();
         for (Object item : source) {
             if(type.isInstance(item))
@@ -749,7 +780,8 @@ public class Util {
      * {@link #rawEncode(String)} should generally be used instead, though be careful to pass only
      * a single path component to that method (it will encode /, but this method does not).
      */
-    public static String encode(String s) {
+    @Nonnull 
+    public static String encode(@Nonnull String s) {
         try {
             boolean escaped = false;
 
@@ -806,7 +838,8 @@ public class Util {
      * single path component used in constructing a URL.
      * Method name inspired by PHP's rawurlencode.
      */
-    public static String rawEncode(String s) {
+    @Nonnull
+    public static String rawEncode(@Nonnull String s) {
         boolean escaped = false;
         StringBuilder out = null;
         CharsetEncoder enc = null;
@@ -855,7 +888,8 @@ public class Util {
     /**
      * Escapes HTML unsafe characters like &lt;, &amp; to the respective character entities.
      */
-    public static String escape(String text) {
+    @Nonnull 
+    public static String escape(@Nonnull String text) {
         if (text==null)     return null;
         StringBuilder buf = new StringBuilder(text.length()+64);
         for( int i=0; i<text.length(); i++ ) {
@@ -888,7 +922,8 @@ public class Util {
         return buf.toString();
     }
 
-    public static String xmlEscape(String text) {
+    @Nonnull
+    public static String xmlEscape(@Nonnull String text) {
         StringBuilder buf = new StringBuilder(text.length()+64);
         for( int i=0; i<text.length(); i++ ) {
             char ch = text.charAt(i);
@@ -906,14 +941,14 @@ public class Util {
     /**
      * Creates an empty file.
      */
-    public static void touch(File file) throws IOException {
+    public static void touch(@Nonnull File file) throws IOException {
         new FileOutputStream(file).close();
     }
 
     /**
      * Copies a single file by using Ant.
      */
-    public static void copyFile(File src, File dst) throws BuildException {
+    public static void copyFile(@Nonnull File src, @Nonnull File dst) throws BuildException {
         Copy cp = new Copy();
         cp.setProject(new org.apache.tools.ant.Project());
         cp.setTofile(dst);
@@ -925,7 +960,8 @@ public class Util {
     /**
      * Convert null to "".
      */
-    public static String fixNull(String s) {
+    @Nonnull
+    public static String fixNull(@CheckForNull String s) {
         if(s==null)     return "";
         else            return s;
     }
@@ -933,7 +969,8 @@ public class Util {
     /**
      * Convert empty string to null.
      */
-    public static String fixEmpty(String s) {
+    @CheckForNull
+    public static String fixEmpty(@CheckForNull String s) {
         if(s==null || s.length()==0)    return null;
         return s;
     }
@@ -943,31 +980,37 @@ public class Util {
      *
      * @since 1.154
      */
-    public static String fixEmptyAndTrim(String s) {
+    @CheckForNull
+    public static String fixEmptyAndTrim(@CheckForNull String s) {
         if(s==null)    return null;
         return fixEmpty(s.trim());
     }
 
-    public static <T> List<T> fixNull(List<T> l) {
+    @Nonnull
+    public static <T> List<T> fixNull(@CheckForNull List<T> l) {
         return l!=null ? l : Collections.<T>emptyList();
     }
 
-    public static <T> Set<T> fixNull(Set<T> l) {
+    @Nonnull
+    public static <T> Set<T> fixNull(@CheckForNull Set<T> l) {
         return l!=null ? l : Collections.<T>emptySet();
     }
 
-    public static <T> Collection<T> fixNull(Collection<T> l) {
+    @Nonnull
+    public static <T> Collection<T> fixNull(@CheckForNull Collection<T> l) {
         return l!=null ? l : Collections.<T>emptySet();
     }
 
-    public static <T> Iterable<T> fixNull(Iterable<T> l) {
+    @Nonnull
+    public static <T> Iterable<T> fixNull(@CheckForNull Iterable<T> l) {
         return l!=null ? l : Collections.<T>emptySet();
     }
 
     /**
      * Cuts all the leading path portion and get just the file name.
      */
-    public static String getFileName(String filePath) {
+    @Nonnull
+    public static String getFileName(@Nonnull String filePath) {
         int idx = filePath.lastIndexOf('\\');
         if(idx>=0)
             return getFileName(filePath.substring(idx+1));
@@ -980,7 +1023,8 @@ public class Util {
     /**
      * Concatenate multiple strings by inserting a separator.
      */
-    public static String join(Collection<?> strings, String separator) {
+    @Nonnull
+    public static String join(@Nonnull Collection<?> strings, @Nonnull String separator) {
         StringBuilder buf = new StringBuilder();
         boolean first=true;
         for (Object s : strings) {
@@ -994,7 +1038,8 @@ public class Util {
     /**
      * Combines all the given collections into a single list.
      */
-    public static <T> List<T> join(Collection<? extends T>... items) {
+    @Nonnull
+    public static <T> List<T> join(@Nonnull Collection<? extends T>... items) {
         int size = 0;
         for (Collection<? extends T> item : items)
             size += item.size();
@@ -1021,7 +1066,8 @@ public class Util {
      *      Can be null.
      * @since 1.172
      */
-    public static FileSet createFileSet(File baseDir, String includes, String excludes) {
+    @Nonnull
+    public static FileSet createFileSet(@Nonnull File baseDir, @Nonnull String includes, @CheckForNull String excludes) {
         FileSet fs = new FileSet();
         fs.setDir(baseDir);
         fs.setProject(new Project());
@@ -1043,7 +1089,8 @@ public class Util {
         return fs;
     }
 
-    public static FileSet createFileSet(File baseDir, String includes) {
+    @Nonnull
+    public static FileSet createFileSet(@Nonnull File baseDir, @Nonnull String includes) {
         return createFileSet(baseDir,includes,null);
     }
 
@@ -1059,7 +1106,8 @@ public class Util {
      * @param symlinkPath
      *      Where to create a symlink in (relative to {@code baseDir})
      */
-    public static void createSymlink(File baseDir, String targetPath, String symlinkPath, TaskListener listener) throws InterruptedException {
+    public static void createSymlink(@Nonnull File baseDir, @Nonnull String targetPath, 
+            @Nonnull String symlinkPath, @Nonnull TaskListener listener) throws InterruptedException {
         try {
             if (createSymlinkJava7(baseDir, targetPath, symlinkPath)) {
                 return;
@@ -1131,7 +1179,7 @@ public class Util {
         }
     }
 
-    private static boolean createSymlinkJava7(File baseDir, String targetPath, String symlinkPath) throws IOException {
+    private static boolean createSymlinkJava7(@Nonnull File baseDir, @Nonnull String targetPath, @Nonnull String symlinkPath) throws IOException {
         try {
             Object path = File.class.getMethod("toPath").invoke(new File(baseDir, symlinkPath));
             Object target = Class.forName("java.nio.file.Paths").getMethod("get", String.class, String[].class).invoke(null, targetPath, new String[0]);
@@ -1201,7 +1249,8 @@ public class Util {
      * @return null
      *      if the specified file is not a symlink.
      */
-    public static File resolveSymlinkToFile(File link) throws InterruptedException, IOException {
+    @CheckForNull
+    public static File resolveSymlinkToFile(@Nonnull File link) throws InterruptedException, IOException {
         String target = resolveSymlink(link);
         if (target==null)   return null;
 
@@ -1221,7 +1270,8 @@ public class Util {
      *      If the symlink is relative, the returned string is that relative representation.
      *      The relative path is meant to be resolved from the location of the symlink.
      */
-    public static String resolveSymlink(File link) throws InterruptedException, IOException {
+    @CheckForNull
+    public static String resolveSymlink(@Nonnull File link) throws InterruptedException, IOException {
         try { // Java 7
             Object path = File.class.getMethod("toPath").invoke(link);
             return Class.forName("java.nio.file.Files").getMethod("readSymbolicLink", Class.forName("java.nio.file.Path")).invoke(null, path).toString();
@@ -1306,7 +1356,8 @@ public class Util {
      * Wraps with the error icon and the CSS class to render error message.
      * @since 1.173
      */
-    public static String wrapToErrorSpan(String s) {
+    @Nonnull
+    public static String wrapToErrorSpan(@Nonnull String s) {
         s = "<span class=error style='display:inline-block'>"+s+"</span>";
         return s;
     }
@@ -1319,7 +1370,8 @@ public class Util {
      * @param defaultNumber number to return if the string can not be parsed
      * @return returns the parsed string; otherwise the default number
      */
-    public static Number tryParseNumber(String numberStr, Number defaultNumber) {
+    @CheckForNull
+    public static Number tryParseNumber(@CheckForNull String numberStr, @CheckForNull Number defaultNumber) {
         if ((numberStr == null) || (numberStr.length() == 0)) {
             return defaultNumber;
         }
@@ -1334,7 +1386,7 @@ public class Util {
      * Checks if the public method defined on the base type with the given arguments
      * are overridden in the given derived type.
      */
-    public static boolean isOverridden(Class base, Class derived, String methodName, Class... types) {
+    public static boolean isOverridden(@Nonnull Class base, @Nonnull Class derived, @Nonnull String methodName, @Nonnull Class... types) {
         try {
             return !base.getMethod(methodName, types).equals(
                     derived.getMethod(methodName,types));
@@ -1349,7 +1401,8 @@ public class Util {
      * @param ext
      *      For example, ".zip"
      */
-    public static File changeExtension(File dst, String ext) {
+    @Nonnull
+    public static File changeExtension(@Nonnull File dst, @Nonnull String ext) {
         String p = dst.getPath();
         int pos = p.lastIndexOf('.');
         if (pos<0)  return new File(p+ext);
@@ -1358,8 +1411,10 @@ public class Util {
 
     /**
      * Null-safe String intern method.
+     * @return A canonical representation for the string object. Null for null input strings
      */
-    public static String intern(String s) {
+    @Nullable
+    public static String intern(@CheckForNull String s) {
         return s==null ? s : s.intern();
     }
 
@@ -1370,7 +1425,7 @@ public class Util {
      * implementing this by ourselves allow it to be more lenient about
      * escaping of URI.
      */
-    public static boolean isAbsoluteUri(String uri) {
+    public static boolean isAbsoluteUri(@Nonnull String uri) {
         int idx = uri.indexOf(':');
         if (idx<0)  return false;   // no ':'. can't be absolute
 
@@ -1382,7 +1437,7 @@ public class Util {
      * Works like {@link String#indexOf(int)} but 'not found' is returned as s.length(), not -1.
      * This enables more straight-forward comparison.
      */
-    private static int _indexOf(String s, char ch) {
+    private static int _indexOf(@Nonnull String s, char ch) {
         int idx = s.indexOf(ch);
         if (idx<0)  return s.length();
         return idx;
@@ -1392,7 +1447,8 @@ public class Util {
      * Loads a key/value pair string as {@link Properties}
      * @since 1.392
      */
-    public static Properties loadProperties(String properties) throws IOException {
+    @Nonnull
+    public static Properties loadProperties(@Nonnull String properties) throws IOException {
         Properties p = new Properties();
         p.load(new StringReader(properties));
         return p;