if (instance == null) { instance = new ColumbaServer(); } return instance;
if (myInstance == null) { myInstance = new MHMessageFileFilter(); } return myInstance;
Clone fragments detected by clone detection tool
File path: /columba-1.4-src/core/src/main/java/org/columba/core/main/ColumbaServer.java File path: /columba-1.4-src/mail/src/main/java/org/columba/mail/folder/mh/MHMessageFileFilter.java
Method name: ColumbaServer getColumbaServer() Method name: MHMessageFileFilter getInstance()
Number of AST nodes: 3 Number of AST nodes: 3
1
if (instance == null) {
1
if (myInstance == null) {
2
			instance = new ColumbaServer();
3
		}
4
		
2
            myInstance = new MHMessageFileFilter();
3
        }
5
return instance;
4
        return myInstance;
Summary
Number of common nesting structure subtrees1
Number of refactorable cases0
Number of non-refactorable cases1
Time elapsed for finding largest common nesting structure subtrees (ms)0.1
Clones locationClones are in different classes
Number of node comparisons5
  1. {Non-refactorable}
    Mapping Summary
    Number of mapped statements1
    Number of unmapped statements in the first code fragment2
    Number of unmapped statements in the second code fragment2
    Time elapsed for statement mapping (ms)0.5
    Clone typeType 2
    Mapped Statements
    ID Statement ID Statement
    1
    if (instance == null)
    1
    if (instance == null)
    1
    if (myInstance == null)
    Differences
    Expression1Expression2Difference
    instancemyInstanceVARIABLE_NAME_MISMATCH
    org.columba.core.main.ColumbaServerorg.columba.mail.folder.mh.MHMessageFileFilterVARIABLE_TYPE_MISMATCH
    Preondition Violations
    Type org.columba.core.main.ColumbaServer of variable instance does not match with type org.columba.mail.folder.mh.MHMessageFileFilter of variable myInstance
    • Make classes org.columba.core.main.ColumbaServer and org.columba.mail.folder.mh.MHMessageFileFilter extend a common superclass
    1
    if (myInstance == null)
                                                                                    
    2
    myInstance = new MHMessageFileFilter();
    Preondition Violations
    Unmatched statement myInstance=new MHMessageFileFilter(); cannot be moved before the extracted code, because it has control dependencies from statements that will be extracted
    2
    myInstance = new MHMessageFileFilter();
    2
    instance = new ColumbaServer();
    2
    instance = new ColumbaServer();
    Preondition Violations
    Unmatched statement instance=new ColumbaServer(); cannot be moved before the extracted code, because it has control dependencies from statements that will be extracted
    Unmatched statement instance=new ColumbaServer(); cannot be moved before or after the extracted code, because it throws exception(s) that should be caught by a try block that will be extracted
                                                                    
                                              
    3
    return myInstance;
    Preondition Violations
    Unmatched return myInstance;
    3
    return myInstance;
    3
    return instance;
    3
    return instance;
    Preondition Violations
    Unmatched return instance;
                                          
    Precondition Violations (7)
    Row Violation
    1Type org.columba.core.main.ColumbaServer of variable instance does not match with type org.columba.mail.folder.mh.MHMessageFileFilter of variable myInstance
    2Unmatched statement myInstance=new MHMessageFileFilter(); cannot be moved before the extracted code, because it has control dependencies from statements that will be extracted
    3Unmatched statement instance=new ColumbaServer(); cannot be moved before the extracted code, because it has control dependencies from statements that will be extracted
    4Unmatched statement instance=new ColumbaServer(); cannot be moved before or after the extracted code, because it throws exception(s) that should be caught by a try block that will be extracted
    5Unmatched return myInstance;
    6Unmatched return instance;
    7The refactoring of the clones is infeasible, because the number of macthed statements is equal to zero