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Pros and Cons of implementing Properties in Java

In C# there exists a type of member that is called a Property. This allows you to easily and simply define a private field and provide simple or complex getters and setters while saving space by not having to define whole methods. Java does not have anything like this, and from what I can see, the general consensus has been to suck it up and define complete getter and setter methods for private variables.
Currently, I have been toying with the following class:
public class Property<T> {
private T value = null;
public Property(){}
public Property(T initialValue){
value = initialValue;
}
public T get(){
return value;
}
public void set(T newValue){
value = newValue;
}
}
With this implementation, you can define simple properties that only require getters and setters:
final Property<String> name = new Property<>("Dog");
Or more advanced options like the one that MSDN provides for C#:
...
public double seconds;
public final Property<Double> Hours = new Property<Double>(){
#Override
public Double get() {
return seconds/3600;
}
#Override
public void set(Double newValue) {
seconds = newValue * 3600;
}
};
...
What would be the pros and cons of this solution?

The pros are largely obvious. I'll point out some that make it better than C#'s properties:
The backing field is tucked away so that you don't accidentally use it instead of the property. (but the downside is that you can't easily choose to use the backing field if you want)
Unlike C#'s auto-properties, you can choose to override only the get or set method, not both, e.g.
public Property<List<String>> MyList = new Property<List<String>>(){
#Override
public List<String> get() {
if (value == null)
value = new ArrayList<String>();
return value;
}
// set still works
};
There are cons, however:
It is not part of the Java language, or any common libraries, so it can be confusing for people who read your code (including yourself in the future).
You cannot change the visibility of the get and set methods: if the Property<T> can be accessed, you can both get and set the value.
If you don't make your Property field final, anyone that can access it can change it to their own Property implementation. This could be useful, but mostly would be a pain.
(this is a con shared with C#'s properties) You can't change the arguments that are passed to the get and set methods. E.g. you can't have a Property<MyType> with both a set(MyType) and a set(CompatibleType) method (unless you extend Property).
Using generics pervasively means that at run-time, (thanks to type erasure) you're using Object pervasively. This boxing/unboxing might make for a slight performance decrease (not noticeable in most apps) if you use primitives (e.g. using double vs Property<Double>).
By the way, Scala is a language that runs on the JVM that includes properties as a native feature, and interoperates with Java's version of properties (getters/setters). You might want to look into that, since basically someone else already hacked the Java language for you. =)
All in all, I'd say you shouldn't try to make Java have properties. When in Rome, do as the Romans do. If you don't like how the Romans do it, move down the street (Scala) or across the country (C#).

So the complete syntax, say for name, would now be:
theObject.name.set("new name");
The point is, how are you accessing that name object? Is it public / protected Then it could be overridden. Is it private? Then you can't change it outside the class anyways.
The solution you've proposed only works if you already have access to the object, at which point you don't need the solution.

The pros of this solution (your anonymous inner class) is that, if you are not needing to implement this anywhere else, it saves you from writing an entire extra class just for this one situation.
The con of this solution is that later you may want to implement it elsewhere, and then you'd want to refactor your code to extract the implementation of Property<Double> into its own class to avoid repeating yourself.
I'd say, if you're pretty sure you're not going to need this implementation anywhere else (I'm guessing you won't), just go ahead with the later solution of an anonymous inner class. It's a good one.

What is the difference...? [C# properties GET/SET ways]

I know in C# you can easily create accessors to a data type, for example, by doing the following:
public class DCCProbeData
{
public float _linearActual { get; set; }
public float _rotaryActual { get; set; }
}
However my colleague, advised me to do it this way:
public class DCCProbeData
{
private float _linearActual = 0f;
public float LinearActual
{
get { return _linearActual; }
set { _linearActual = value; }
}
private float _rotaryActual = 0f;
public float RotaryActual
{
get { return _rotaryActual; }
set { _rotaryActual = value; }
}
}
My way seems simpler, and more concise. What are the differences and benefits of doing it either way?
Thanks
Edit Just a note, my colleague was able to generate the code for the "second way" using the Refactor option within the Class Details pane most easily found in a Diagram file. This makes it easy to add many Properties without having to manually create the accessors.

"Your way" just tells the compiler to create the second option. Unless you do something else in the getter or setter, they are functionally identical.
However, with "your way", I would recommend using the proper C# naming conventions. I would personally write this as:
public class DccProbeData
{
public float LinearActual { get; set; }
public float RotaryActual { get; set; }
}

The only difference is that you've named the fields.
(I'd stick with your colleagues naming convention for public properties though.)

They do the same thing internally. The only difference is that you cannot directly access the backing field variable using Auto Implemented Properties.

They are technically the same... the get/set is shorthand (auto property).
Lots of questions on SO about this:
When to use get; set; in c#
What is the { get; set; } syntax in C#?
Auto-Implemented Properties c#

Your way doesn't allow you to initialize the values, and your colleague's way follows a more-standard naming convention.

I would like to add something that I haven't seen in the other answers, which makes #2 a better choice:
Using the first method you cannot set a breakpoint on the get and set.
Using the second method you can set a breakpoint on the get and set, which is very helpful for debugging anything accessing your private variable.

Okay, the names have been mentioned before. It's also worth noting that as well as not being with the normal .NET conventions, beginning a public name with an underscore is not CLS-compliant (indeed, one reason for using it for private names is precisely because of this, it makes the distinction clearer, and should result in a warning with some code-checkers if you accidentally have the wrong access level).
Names aside, the one advantage to the latter form is that you can add more complicated code. Still, it's a non-breaking change to go from the former style to the latter, so there's no reason to do it before it's needed.

The first way is the way to go when you need simple properties with get and set and private storage done for you.
Use the second way if you need to do something special when you get or set the value.
Also, I recommend you stick to naming conventions using FxCop or ReSharper.

I believe at the IL level, they both end up the same. In the background, VS creates autonamed variables for you when using the auto getters and setters.

The only way this could possibly be better is if you feel you will be adding more logic to the getters and setters at a later date.
Even then, this seems a little pointless.

They are the same in the sense that your code sample will automatically generate backing fields.
But the two code samples are different because the names of the properties are not the same (LinearActual vs linearActual)

There is no difference, however prior to C# 3 you had to use the long way. At the end of the day it's a C# feature - syntactic sugar. They are both functionally identical.

Things you can do when you don't use auto-implemented properties:
initialize to a default value
access or annotate the backing field (attributes)
read-only backing fields or immutability
set a breakpoint on access
have custom code around access to the variable
Use [System.ComponentModel.EditorBrowsableAttribute()] to enable custom logic on the accessors that you avoid accidently bypassing while coding
hides the backing field from intellisense
Conversion between the two ways is made very simple with ReSharper.
This is not to say don't use them by all means use them, unless you have a need for any of the other functionality listed.

Private Set or Private member?

I was wondering what's considered the C# best practice, private/protected members with public getters, or public getters with private/protected setters?
public int PublicGetPrivateSetter
{
get;
private set;
}
private int _privateMember;
public int PublicGetPrivateMember
{
get { return _privateMember; }
}
I feel that using a private member is more explicit in your code that it's a private setter (using naming conventions).
On the other hand using private setters gives you an option to use virtual (protected), write less code, has less room for mistakes and can give you an option to add a side effect later on if you need to.
I couldn't find what's considered a best practice, or even if one is considered better than the other. From what I've seen usually 80% of the time (from code that I'VE seen) people DONT use private setters... I'm not sure if this is because people don't know about private setters, or because it's considered better to actually use private members.
EDIT:
Indeed, other benefits which I forgot about when using private members is default values and the use of readonly.

I prefer to use auto-implemented properties unless the default implementation doesn't do what I want. So in this case, since the auto-implemented property does what you need, just use that:
public int Foo { get; private set; }
However another situation is if you want to make the field readonly (meaning that the only place where the field can be set is in the constructor). Then you need to define the backing field and mark it readonly as this isn't supported by auto-implemented properties:
private readonly int foo;
public int Foo
{
get { return foo; }
}

There is no best practice I'm aware of. I know automatic properties were mainly to make things easier even more easier for code generation and LINQ related stuff.
For me, I start with automatic properties and refactor later if needed. Depending on the need I may change something to virtual or protected as you mentioned, or maybe refactor to use a variable (When I want to refactor the set accessor to have some logic.

Its the same thing. In the first example, the compiler generates the backing store. In the second, you generated the backing store. Since the implementation is internal to the class, refactoring one into the other is not a big deal. Tools like Resharper make that trivial. The reason you probably haven't seen private setters that much is that its a C# 3.0 feature.

There's nothing wrong with private setters. In most case, it's used with auto properties to make the property readonly outside the object's scope.

Conceptualy speaking, it doesn't change anything. It's mostly a matter of taste.
I personnally use the private setter because I'm lazy and use the propg snippet a lot. (propg tab tab)
Also, most of the time I end up setting dirty flags and binding events to those properties, so I might as well do a part of the work right now. If you ever need to add a setter later, it's much easier if the code is written without using the member behind since the beggining as it will be less code to change.

There is no good answer to this question. the best pratice is to follow our compagnie nomenclature and if your alone then the way you prefer

In my opinion there is no best practice and very little (if any) difference in the resulting compiled code, it really just depends on your needs or own likes/dislikes. If you're following your group's naming standards and meeting requirements (e.g. don't need to propagate a change notification) then it shouldn't matter.
An advantage of private fields is that you can define a default value in the same place as your declaration. In an auto-implemented property you'll have do define the default in the constructor if it's not null or the type's default value.
However, I still like private setters. But we usually don't use auto-implemented properties since our setters usually have a richer functionality - e.g. property update notifications, logging, etc.

Data encapsulation in C# using properties

currently I am thinking about data encapsulation in C# and I am a little bit confused.
Years ago, when I started to learn programing with C++, my professor told me:
- "Create a class and hide it data members, so it can't be manipulated directly from outside"
Example:
You are parsing an XML file and store the parsed data into some data members inside the parser class.
Now, when I am looking at C#. You have there properties. This feature makes the internal state / internal data of a class visible to outside.
There is no encapsulation anymore. Right?
private string _mystring;
public string MyString
{
get {return _mystring;}
set {_mystring = value;}
}
From my point of view there is no difference between making data members public or having public properties, which have getters and setters, where you pass your private data members through.
Can someone explaing me that please?
Thanks

The private data is encapsulated by the property itself. The only way to access the data is through the property.
In your situation above, there is little reason to use the property. However, if you later need to add some validation, you can, without breaking the API, ie::
private string _mystring;
public string MyString
{
get {return _mystring;}
set
{
if (IsAcceptableInput(value))
_mystring = value;
}
}
Remember that a Property, in .NET, is really just a cleaner syntax for 2 methods - one method for the property get section, and one for the property set section. It provides all of the same encapsulation as a pair of methods in C++, but a (arguably) nicer syntax for usage.

Well so properties aren't the wild west you are taking them to be at a first glance. The unfortunate truth of OOP is that a lot of your methods are getters and setters, and properties are just a way to make this easier to write. Also you control what you'd like the property to allow someone to do. You can make a property readable but not writable, like so:
private string _mystring;
public string MyString
{
get {return _mystring;}
}
Or as mentioned by Reed you can have your set method do a transformation or checking of any amount of complexity. For instance something like
private long myPrime;
public long Prime {
get { return myPrime; }
set {
if (prime(value) {
myPrime = prime;
}
else {
//throw an error or do nothing
}
}
}
You generally have all the value you get from encapsulation, with some syntactic sugar to make some common tasks easier. You can do the same thing properties do in other languages, it just looks different.

The benefit of properties is that later on, you could decide to add validation etc to the setter method, or make the getter method do some calculation or caching, and none of the code that already calls your property would need to change - since the class' interface remained stable

There still is data encapsulation, if you need it to be. Encapsulating data is not about hiding it from the client of the class or making it unaccessible, it's about ensuring a consistent interface and internal object state.
Let's say you have an object representing a stick shift car, and a property to set the speed. You probably know that you should shift gears in between speed intervals, so that's where encapsulation comes in.
Instead of simply making the property public, thus allowing public access without any verification, you can use property getters and setters in C#:
class StickShiftCar : Car
{
public int MilesPerHour
{
get {return this._milesPerHour;}
set
{
if (vaule < 20)
this._gearPosition = 1;
else if (value > 30)
this._gearPosition = 2;
...
...
this._milesPerHour = value;
}
}
While this example is not necessarily compilable, I am sure you catch my drift.

You may be missing the fact that you don't have to have properties to correspond to all class member fields. You can decide which properties to add to your class, and whether or not they will be accessible outside of the class.

Looking a bit deeper, why did your professor tell you to encapsulate? Just because it is the proper object-oriented design? Why is that the proper way? Programming languages and paradigms are just a way of coping with the complexity of getting a processor to run our code in an understandable way. There are two readers of code, the machine and humans. The machine will happily load data from, or branch to, any address in the memory space. We humans on the other hand like to think of "things". Our brains deal with "things" that have attributes or that perform actions. A lion will eat you, a spear can defend you, a lion is furry, a spear is pointy. So we can understand programs if they are modeled as "things". Properties are supposed to model the attributes of a thing, and methods are supposed to model the things actions. In practice it can become quite fuzzy and everything cannot be modeled as a real world action, but the effort to do so, when done well, can make a program understandable.

The very first attempt of using property to encapsulate the value is get;set;
But C# provide more advanced feature to enrich functions inside get and set to make the property read-only, write-only or with certain conditions.
For example, to set the value as
private string temp;
public string temp
{
get
{
return temp;
}
}
will be better than using:
public readonly string Temp;

Are there any reasons to use private properties in C#?

I just realized that the C# property construct can also be used with a private access modifier:
private string Password { get; set; }
Although this is technically interesting, I can't imagine when I would use it since a private field involves even less ceremony:
private string _password;
and I can't imagine when I would ever need to be able to internally get but not set or set but not get a private field:
private string Password { get; }
or
private string Password { set; }
but perhaps there is a use case with nested / inherited classes or perhaps where a get/set might contain logic instead of just giving back the value of the property, although I would tend to keep properties strictly simple and let explicit methods do any logic, e.g. GetEncodedPassword().
Does anyone use private properties in C# for any reason or is it just one of those technically-possible-yet-rarely-used-in-actual-code constructs?
Addendum
Nice answers, reading through them I culled these uses for private properties:
when private fields need to be lazily loaded
when private fields need extra logic or are calculated values
since private fields can be difficult to debug
in order to "present a contract to yourself"
to internally convert/simplify an exposed property as part of serialization
wrapping global variables to be used inside your class

I use them if I need to cache a value and want to lazy load it.
private string _password;
private string Password
{
get
{
if (_password == null)
{
_password = CallExpensiveOperation();
}
return _password;
}
}

The primary usage of this in my code is lazy initialization, as others have mentioned.
Another reason for private properties over fields is that private properties are much, much easier to debug than private fields. I frequently want to know things like "this field is getting set unexpectedly; who is the first caller that sets this field?" and it is way easier if you can just put a breakpoint on the setter and hit go. You can put logging in there. You can put performance metrics in there. You can put in consistency checks that run in the debug build.
Basically, it comes down to : code is far more powerful than data. Any technique that lets me write the code I need is a good one. Fields don't let you write code in them, properties do.

perhaps there is a use case with nested / inherited classes or perhaps where a get/set might contain logic instead of just giving back the value of the property
I personally use this even when I don't need logic on the getter or setter of a property. Using a property, even a private one, does help future-proof your code so that you can add the logic to a getter later, if required.
If I feel that a property may eventually require extra logic, I will sometimes wrap it into a private property instead of using a field, just so I don't have to change my code later.
In a semi-related case (though different than your question), I very frequently use the private setters on public properties:
public string Password
{
get;
private set;
}
This gives you a public getter, but keeps the setter private.

One good usage for private get only properties are calculated values. Several times I've had properties which are private readonly and just do a calculation over other fields in my type. It's not worthy of a method and not interesting to other classes so private property it is.

Lazy initialization is one place where they can be neat, e.g.
private Lazy<MyType> mytype = new Lazy<MyType>(/* expensive factory function */);
private MyType MyType { get { return this.mytype.Value; } }
// In C#6, you replace the last line with: private MyType MyType => myType.Value;
Then you can write: this.MyType everywhere rather than this.mytype.Value and encapsulate the fact that it is lazily instantiated in a single place.
One thing that's a shame is that C# doesn't support scoping the backing field to the property (i.e. declaring it inside the property definition) to hide it completely and ensure that it can only ever be accessed via the property.

The only one usage that I can think of
private bool IsPasswordSet
{
get
{
return !String.IsNullOrEmpty(_password);
}
}

Properties and fields are not one to one. A property is about the interface of a class (whether talking about its public or internal interface), while a field is about the class's implementation. Properties should not be seen as a way to just expose fields, they should be seen as a way to expose the intent and purpose of the class.
Just like you use properties to present a contract to your consumers on what constitutes your class, you can also present a contract to yourself for very similar reasons. So yes, I do use private properties when it makes sense. Sometimes a private property can hide away implementation details like lazy loading, the fact that a property is really a conglomeration of several fields and aspects, or that a property needs to be virtually instantiated with each call (think DateTime.Now). There are definitely times when it makes sense to enforce this even on yourself in the backend of the class.

I use them in serialization, with things like DataContractSerializer or protobuf-net which support this usage (XmlSerializer doesn't). It is useful if you need to simplify an object as part of serialization:
public SomeComplexType SomeProp { get;set;}
[DataMember(Order=1)]
private int SomePropProxy {
get { return SomeProp.ToInt32(); }
set { SomeProp = SomeComplexType.FromInt32(value); }
}

I use private properties to reduce code for accessing sub properties which often to use.
private double MonitorResolution
{
get { return this.Computer.Accesories.Monitor.Settings.Resolution; }
}
It is useful if there are many sub properties.

One thing I do all the time is store "global" variables/cache into HttpContext.Current
private static string SomeValue{
get{
if(HttpContext.Current.Items["MyClass:SomeValue"]==null){
HttpContext.Current.Items["MyClass:SomeValue"]="";
}
return HttpContext.Current.Items["MyClass:SomeValue"];
}
set{
HttpContext.Current.Items["MyClass:SomeValue"]=value;
}
}

I use them every now and then. They can make it easier to debug things when you can easily put in a breakpoint in the property or you can add a logging statement etc.
Can be also be useful if you later need to change the type of your data in some way or if you need to use reflection.

I know this question is very old but the information below was not in any of the current answers.
I can't imagine when I would ever need to be able to internally get but not set
If you are injecting your dependencies you may well want to have a Getter on a Property and not a setter as this would denote a readonly Property. In other words the Property can only be set in the constructor and cannot be changed by any other code within the class.
Also Visual Studio Professional will give information about a Property and not a field making it easier to see what your field is being used.

It is a common practice to only modify members with get/set methods, even private ones. Now, the logic behind this is so you know your get/set always behave in a particular way (for instance, firing off events) which doesn't seem to make sense since those won't be included in the property scheme... but old habits die hard.

It makes perfect sense when there is logic associated with the property set or get (think lazy initialization) and the property is used in a few places in the class.
If it's just a straight backing field? Nothing comes to mind as a good reason.

Well, as no one mentioned you can use it to validate data or to lock variables.
Validation
string _password;
string Password
{
get { return _password; }
set
{
// Validation logic.
if (value.Length < 8)
{
throw new Exception("Password too short!");
}
_password = value;
}
}
Locking
object _lock = new object();
object _lockedReference;
object LockedReference
{
get
{
lock (_lock)
{
return _lockedReference;
}
}
set
{
lock (_lock)
{
_lockedReference = value;
}
}
}
Note: When locking a reference you do not lock access to members of the referenced object.
Lazy reference: When lazy loading you may end up needing to do it async for which nowadays there is AsyncLazy. If you are on older versions than of the Visual Studio SDK 2015 or not using it you can also use AsyncEx's AsyncLazy.

One more usage would be to do some extra operations when setting value.
It happens in WPF in my case, when I display some info based on private object (which doesn't implement INotifyPropertyChanged):
private MyAggregateClass _mac;
private MyAggregateClass Mac
{
get => _mac;
set
{
if(value == _mac) return;
_mac = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(DisplayInfo)));
}
}
public string DisplayInfo => _mac.SomeStringInformationToDisplayOnUI;
One could also have some private method, such as
private void SetMac(MyAggregateClass newValue)
to do that.

Some more exotic uses of explicit fields include:
you need to use ref or out with the value - perhaps because it is an Interlocked counter
it is intended to represent fundamental layout for example on a struct with explicit layout (perhaps to map to a C++ dump, or unsafe code)
historically the type has been used with BinaryFormatter with automatic field handling (changing to auto-props changes the names and thus breaks the serializer)

Various answers have mentioned using properties to implement a lazy member. And this answer discussed using properties to make live aliases. I just wanted to point out that those two concepts sometimes go together.
When using a property to make an alias of another object's public property, the laziness of that property is preserved:
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
private IDbConnection Conn => foo.bar.LazyDbConnection;
On the other hand, retrieving that property in the constructor would negate the lazy aspect:
Conn = foo.bar.LazyDbConnection;

Looking into the guideline (Properties (C# Programming Guide)) it seems no one expects to use properties as private members.
Properties enable a class to expose a public way of getting and setting values, while hiding implementation or verification code.
In any case it can be interchanged by one or two methods and vice versa.
So the reason can be to spare parentheses on getting and get field syntax on setting.