California Civil Procedure Code
The testimony of witnesses is taken in three modes: 1. By affidavit;
2. By deposition;
3. By oral examination.
An affidavit is a written declaration under oath, made without notice to the adverse party.
A deposition is a written declaration, under oath, made upon notice to the adverse party, for the purpose of enabling him to attend and cross-examine. In all actions and proceedings where the default of the defendant has been duly entered, and in all proceedings to obtain letters of administration, or for the probate of wills and the issuance of letters testamentary thereon, where, after due and legal notice, those entitled to contest the application have failed to appear, the entry of said defaults, and the failure of said persons to appear after notice, shall be deemed to be a waiver of the right to any further notice of any application or proceeding to take testimony by deposition in such action or proceeding.
An oral examination is an examination in presence of the jury or tribunal which is to decide the fact or act upon it, the testimony being heard by the jury or tribunal from the lips of the witness.