Fixed the LeftCurly check to ignore leading annotations. Thanks to Tim Carpenter for patch #2506439. An excellent quality patch.

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheck.java

@@ -126,7 +126,11 @@ public class LeftCurlyCheck
         switch (aAST.getType()) {
         case TokenTypes.CTOR_DEF :
         case TokenTypes.METHOD_DEF :
-            startToken = aAST;
+            // Orig
+            //startToken = aAST;
+            // New
+            startToken = skipAnnotationOnlyLines(aAST);
+            // End
             brace = aAST.findFirstToken(TokenTypes.SLIST);
             break;
 
@@ -135,11 +139,11 @@ public class LeftCurlyCheck
         case TokenTypes.ANNOTATION_DEF :
         case TokenTypes.ENUM_DEF :
         case TokenTypes.ENUM_CONSTANT_DEF :
-            startToken = aAST.getFirstChild();
+            startToken = (DetailAST) skipAnnotationOnlyLines(aAST);
             final DetailAST objBlock = aAST.findFirstToken(TokenTypes.OBJBLOCK);
             brace = (objBlock == null)
                 ? null
-                : objBlock.getFirstChild();
+                : (DetailAST) objBlock.getFirstChild();
             break;
 
         case TokenTypes.LITERAL_WHILE:
@@ -156,7 +160,7 @@ public class LeftCurlyCheck
 
         case TokenTypes.LITERAL_ELSE :
             startToken = aAST;
-            final DetailAST candidate = aAST.getFirstChild();
+            final DetailAST candidate = (DetailAST) aAST.getFirstChild();
             brace =
                 (candidate.getType() == TokenTypes.SLIST)
                 ? candidate
@@ -178,6 +182,62 @@ public class LeftCurlyCheck
         }
     }
 
+    /**
+     * Skip lines that only contain <code>TokenTypes.ANNOTATION</code>s.
+     * If the received <code>DetailAST</code>
+     * has annotations within its modifiers then first token on the line
+     * of the first token afer all annotations is return. This might be
+     * an annotation.
+     * Otherwise, the received <code>DetailAST</code> is returned.
+     * @param aAST <code>DetailAST</code>.
+     * @return <code>DetailAST</code>.
+     */
+    private DetailAST skipAnnotationOnlyLines(DetailAST aAST)
+    {
+        final DetailAST modifiers = aAST.findFirstToken(TokenTypes.MODIFIERS);
+        if (modifiers == null) {
+            return aAST;
+        }
+        DetailAST lastAnnot = findLastAnnotation(modifiers);
+        if (lastAnnot == null) {
+            // There are no annotations.
+            return aAST;
+        }
+        final DetailAST tokenAfterLast = lastAnnot.getNextSibling() != null
+                                       ? lastAnnot.getNextSibling()
+                                       : modifiers.getNextSibling();
+        if (tokenAfterLast.getLineNo() > lastAnnot.getLineNo()) {
+            return tokenAfterLast;
+        }
+        else {
+            final int lastAnnotLineNumber = lastAnnot.getLineNo();
+            while (lastAnnot.getPreviousSibling() != null
+                   && (lastAnnot.getPreviousSibling().getLineNo()
+                        == lastAnnotLineNumber))
+            {
+                lastAnnot = lastAnnot.getPreviousSibling();
+            }
+            return lastAnnot;
+        }
+    }
+
+    /**
+     * Find the last token of type <code>TokenTypes.ANNOTATION</code>
+     * under the given set of modifiers.
+     * @param aModifiers <code>DetailAST</code>.
+     * @return <code>DetailAST</code> or null if there are no annotations.
+     */
+    private DetailAST findLastAnnotation(DetailAST aModifiers)
+    {
+        DetailAST aAnnot = aModifiers.findFirstToken(TokenTypes.ANNOTATION);
+        while (aAnnot != null && aAnnot.getNextSibling() != null
+               && aAnnot.getNextSibling().getType() == TokenTypes.ANNOTATION)
+        {
+            aAnnot = aAnnot.getNextSibling();
+        }
+        return aAnnot;
+    }
+
     /**
      * Verifies that a specified left curly brace is placed correctly
      * according to policy.

src/testinputs/com/puppycrawl/tools/checkstyle/InputLeftCurlyAnnotations.java

@@ -0,0 +1,59 @@
+package com.puppycrawl.tools.checkstyle;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import java.util.ArrayList;
+import java.util.List;
+
+@TestClassAnnotation
+class InputLeftCurlyAnnotations 
+{
+    private static final int X = 10;
+    @Override
+    public boolean equals(Object other)
+    {
+        return false;
+    }
+    
+    @Override
+    @SuppressWarnings("unused")
+    public int hashCode() 
+    {
+        int a = 10;
+        return 1;
+    }
+    
+    @Override @SuppressWarnings({"unused", "unchecked", "static-access"}) public String toString()
+    {
+        Integer i = this.X;
+        List<String> l = new ArrayList();
+        return "SomeString";
+    }
+}
+
+@TestClassAnnotation
+class InputLeftCurlyAnnotations2 {
+    private static final int X = 10;
+    @Override
+    public boolean equals(Object other) {
+        return false;
+    }
+    
+    @Override
+    @SuppressWarnings("unused")
+    public int hashCode() {
+        int a = 10;
+        return 1;
+    }
+    
+    @Override @SuppressWarnings({"unused", "unchecked", "static-access"}) public String toString()
+    {
+        Integer i = this.X;
+        List<String> l = new ArrayList();
+        return "SomeString";
+    }
+}
+
+@Target(ElementType.TYPE)
+@interface TestClassAnnotation {
+}

src/tests/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckTest.java

@@ -119,7 +119,7 @@ public class LeftCurlyCheckTest extends BaseCheckTestSupport
         };
         verify(mCheckConfig, getPath("InputLeftCurlyOther.java"), expected);
     }
-
+    
     @Test
     public void testNL3() throws Exception
     {
@@ -146,4 +146,28 @@ public class LeftCurlyCheckTest extends BaseCheckTestSupport
         };
         verify(mCheckConfig, getPath("InputBraces.java"), expected);
     }
+    
+    @Test
+    public void testDefaultWithAnnotations() throws Exception
+    {
+        final String[] expected = {
+            "10:1: '{' should be on the previous line.",
+            "14:5: '{' should be on the previous line.",
+            "21:5: '{' should be on the previous line."
+        };
+        verify(mCheckConfig, getPath("InputLeftCurlyAnnotations.java"), expected);
+    }
+    
+    @Test
+    public void testNLWithAnnotations() throws Exception
+    {
+        mCheckConfig.addAttribute("option", LeftCurlyOption.NL.toString());
+        final String[] expected = { 
+            "35:34: '{' should be on a new line.",
+            "38:41: '{' should be on a new line.",
+            "44:27: '{' should be on a new line.",
+            "58:32: '{' should be on a new line."
+        };
+        verify(mCheckConfig, getPath("InputLeftCurlyAnnotations.java"), expected);
+    }
 }

src/xdocs/releasenotes.xml

@@ -112,6 +112,11 @@
           user specifies a directory with the <i>-r</i> option that does
           not contain any files. Thanks to Florian for patch #2151706.
         </li>
+        <li>
+          Fixed the <a href="config_blocks.html#LeftCurly">LeftCurly</a> check
+          to ignore leading annotations. Thanks to Tim Carpenter for patch
+          #2506439.
+        </li>
       </ul>
 
       <p>Notes:</p>