C# to Java Converter FAQ

Q: Are the original C# files altered in any way?

Your existing code is left completely intact. The new Java files are output to the new location that you specify.

Q: What version of C# is converted?

We attempt to convert as much as possible and are continually updating the converter to handle newer C# features. However, many new C# features have no Java equivalent so the output will require adjustments.

Q: What is the conversion accuracy?

Our accuracy is very high, but there will be significant adjustments required for all but the simplest conversions. There are no direct equivalents for some aspects of C#. Read the rest of the FAQ to get an idea of a few things that are not converted. C# to Java Converter is intended to reduce the amount of work you'll have to do to convert code to Java, but it is just the first step.

Q: Are C# delegates converted?

Yes — try out our Free Edition to see the conversion details. We convert delegate declarations to interface declarations and references to delegate instances to lambdas.

Q: Are C# events converted?

Yes — try out our Free Edition to see the conversion details. We substitute a wrapper type (using Java generics) for the event delegate type. This generic type maintains collections of 'listeners' with methods to add or remove listeners.

Q: Are C# ref parameters converted?

Yes — try out our Free Edition to see the conversion details. We substitute a wrapper type (using Java generics) for the parameter type and adjust all references to the parameter in the defining method and all calls to the method.

Q: How are C# methods with optional parameters converted?

Overloaded methods are created. Missing arguments are replaced by the defaults specified by the original C# parameter list.

Q: What about .NET UI code?

The converter does not convert .NET UI types due to the lack of similarity between these types and Java UI types.

Q: What are the most common adjustments necessary after conversion?

'unsafe' code blocks and types are not converted.
C# to Java Converter converts only some .NET types to Java equivalents. The converter offers options to use your own custom replacements.
C# events of delegate types that are not defined in the converted code and also not one of the System.Action or System.Func delegates are not converted.
Since Java lacks a preprocessor, all code dependent on conditional compilation needs to be refactored so that the functionality can be achieved in other ways.
C# LINQ query syntax is not converted since this feature is not available in Java (but LINQ method syntax is partially converted).
C# 'struct' is converted to Java 'class', since Java does not include value types. We add a 'clone' method to the Java class to try to reproduce the same behavior as .NET value types, but adjustments may still be required.
C# nullable logic cannot be converted since the necessary null-value logic must be applied to every aspect of expressions containing the nullable variable or method call. The only aspect of nullable instances that is converted is the declared type — the corresponding Java wrapper type is used for nullable primitives (e.g., the Java wrapper type 'Integer' is used for C# int? or Nullable<int>).
Unfortunately, many new C# features beginning with C# 7 have no equivalent in other languages.

Additional Resources

Java and C# comparison and equivalents chart