diff --git a/src/org/ntlab/deltaExtractor/Alias.java b/src/org/ntlab/deltaExtractor/Alias.java
index 7d83a6e..5477266 100644
--- a/src/org/ntlab/deltaExtractor/Alias.java
+++ b/src/org/ntlab/deltaExtractor/Alias.java
@@ -1,72 +1,76 @@
-package org.ntlab.deltaExtractor;
-import org.ntlab.trace.MethodExecution;
-import org.ntlab.trace.Statement;
-import org.ntlab.trace.TracePoint;
-/**
- * �I�u�W�F�N�g�̎Q�Ə��(�G�C���A�X)��\���N���X
- * @author Isitani
- *
- */
-public class Alias {
-	private String objectId;
-	private TracePoint occurrencePoint; // ���Y�I�u�W�F�N�g�̎Q�Ƃ��s���Ă�����s�ӏ��ɑΉ�����TracePoint
-	private AliasType aliasType;
-	private int index;
-	
-	public enum AliasType {
-		// ���\�b�h�ւ̓���
-		FORMAL_PARAMETER, 
-		THIS, 
-		METHOD_INVOCATION, 
-		CONSTRACTOR_INVOCATION, 
-		
-		// �ǐՃI�u�W�F�N�g�̐؂�ւ�
-		FIELD, 
-		CONTAINER, 
-		ARRAY_ELEMENT, 
-		ARRAY, 
-		ARRAY_CREATE, 
-
-		// ���\�b�h����̏o��
-		ACTUAL_ARGUMENT, 
-		RECEIVER, 
-		RETURN_VALUE
-	}
-	
-	public Alias(AliasType aliasType, int index, String objectId, TracePoint occurrencePoint) {
-		this.aliasType = aliasType;
-		this.index = index;
-		this.objectId = objectId;
-		this.occurrencePoint = occurrencePoint;
-	}
-	
-	public AliasType getAliasType() {
-		return aliasType;
-	}
-	
-	public int getIndex() {
-		return index;
-	}
-	
-	public String getObjectId() {
-		return objectId;
-	}
-	
-	public TracePoint getOccurrencePoint() {
-		return occurrencePoint;
-	}
-	
-	public MethodExecution getMethodExecution() {
-		return occurrencePoint.getMethodExecution();
-	}
-	
-	public String getMethodSignature() {
-		return occurrencePoint.getMethodExecution().getCallerSideSignature();
-	}
-	
-	public int getLineNo() {
-		Statement statement = occurrencePoint.getStatement();
-		return statement.getLineNo();
-	}
-	
+package org.ntlab.deltaExtractor;
+import org.ntlab.trace.MethodExecution;
+import org.ntlab.trace.Statement;
+import org.ntlab.trace.TracePoint;
+/**
+ * �I�u�W�F�N�g�̎Q�Ə��(�G�C���A�X)��\���N���X
+ * @author Isitani
+ *
+ */
+public class Alias {
+	private String objectId;
+	private TracePoint occurrencePoint; // ���Y�I�u�W�F�N�g�̎Q�Ƃ��s���Ă�����s�ӏ��ɑΉ�����TracePoint
+	private AliasType aliasType;
+	private int index;
+	
+	public enum AliasType {
+		// ���\�b�h�ւ̓���
+		FORMAL_PARAMETER, 
+		THIS, 
+		METHOD_INVOCATION, 
+		CONSTRACTOR_INVOCATION, 
+		
+		// �ǐՃI�u�W�F�N�g�̐؂�ւ�
+		FIELD, 
+		CONTAINER, 
+		ARRAY_ELEMENT, 
+		ARRAY, 
+		ARRAY_CREATE, 
+
+		// ���\�b�h����̏o��
+		ACTUAL_ARGUMENT, 
+		RECEIVER, 
+		RETURN_VALUE
+	}
+	
+	public Alias(AliasType aliasType, int index, String objectId, TracePoint occurrencePoint) {
+		this.aliasType = aliasType;
+		this.index = index;
+		this.objectId = objectId;
+		this.occurrencePoint = occurrencePoint;
+	}
+	
+	public AliasType getAliasType() {
+		return aliasType;
+	}
+	
+	public int getIndex() {
+		return index;
+	}
+	
+	public String getObjectId() {
+		return objectId;
+	}
+	
+	public TracePoint getOccurrencePoint() {
+		return occurrencePoint;
+	}
+	
+	public MethodExecution getMethodExecution() {
+		return occurrencePoint.getMethodExecution();
+	}
+	
+	public String getMethodSignature() {
+		return occurrencePoint.getMethodExecution().getCallerSideSignature();
+	}
+	
+	public int getLineNo() {
+		try {
+			Statement statement = occurrencePoint.getStatement();
+			return statement.getLineNo();
+		} catch (Exception e) {
+			return -1;
+		}
+	}
+	
 }
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