Correct use of "but", "however" and "although"

I am not sure which conjunction to use in the following context:

1. I know about programming but I have a little bit of confusion in Java programming.
2. I know about programming although I have a little bit of confusion in programming.
3. I know about programming however I have a little bit of confusion in Java programming.

Solution 1:

Your sentences #1 and #2 are both correct, so long as you add a comma after "programming":

I know about programming, [but/although] I have a little bit of confusion in Java programming.

In almost all situations but and although are synonyms. Although is slightly more formal, and is preferred if you want to stress that both halves of your statement may be true. But is used when you wish to stress contradiction between the halves of the statement. For example:

She said the book was blue, but I think that it's green. [Contradiction: prefer but.]

Usually we speak in English, although we sometimes use Russian. [Both halves are true: prefer although.]

Note that this is not a firm rule, since you could use either but or although in both of the sentences above without it being wrong.

However is a different matter. However is an adverb, and it's used to introduce a new sentence in circumstances where you would otherwise use but to join the sentences. So your example #3 should be:

I know about programming. However, I have a little bit of confusion in Java programming.

(Final note: "a little bit confusion" is grammatically incorrect. You need to add the word "of": a little bit of confusion.)

Solution 2:

Sentence #2 is correct as it is written. Sentence #1 needs a comma. Sentence #3 needs to be separated into two clauses. This can be done with a period or a semicolon.

Sentence #1 uses but, which is a coordinating conjunction. When two independent clauses are joined with a coordinating conjunction, a comma should be added to separate both parts of the compound sentence.

1. I know about programming, but I have a little bit of confusion in Java programming.

Sentence #2 is correct as it is. As noted by SF, although can be used at the beginning of the sentence. If the two clauses are reversed, the sentence will require a comma. As it is now, the sentence does not require a comma. Here is the basic rule for combining two clauses with a subordinating conjunction such as although: if the sentence begins with the conjunction, add a comma in the middle; if the subordinating conjunction is in the middle of the sentence, no comma is needed.

2a. I know about programming although I have a little bit of confusion about Java programming.

2b. Although I have a little bit of confusion in Java programming, I know about programming.

Sentence 3 uses however. However is a conjunctive adverb. There are a few ways to use however correctly, but it cannot be a substitute for but. The easy solution is to separate the two clauses with a period or a semicolon, and begin the second clause with the conjunctive adverb.

3a. I know about programming. However, I have a little bit of confusion about Java programming.

3b. I know about programming; however, I have a little bit of confusion about Java programming.

Some conjunctive adverbs, such as however, can be used another way. The clauses still need to be separated, but however does not always have to begin the second clause. It can often be "worked in" to the second clause next to the main action verb. This is usually more fluent when an auxiliary verb such as do is present.

3c. I know about programming; I do, however, have a little bit of confusion about Java programming.